diff --git a/.eslintrc b/.eslintrc
index fd9bb8ddc..d6b20038b 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -16,6 +16,8 @@
     "@typescript-eslint/no-unused-vars": ["error", {
       "args": "none"
     }],
-    "no-unused-vars": "off"
+    "no-unused-vars": "off",
+    "no-var": "error",
+    "prefer-const": "error"
   }
 }
diff --git a/package.json b/package.json
index ce4ede68c..33af3bd31 100644
--- a/package.json
+++ b/package.json
@@ -17,7 +17,8 @@
     "docs:start": "cd docs && yarn start",
     "pretest": "yarn build",
     "prepublish": "yarn build",
-    "lint": "eslint --cache 'packages/**/*.{js,ts,tsx}'"
+    "lint": "eslint --cache 'packages/**/*.{js,ts,tsx}'",
+    "lint:fix": "eslint --cache 'packages/**/*.{js,ts,tsx}' --fix"
   },
   "devDependencies": {
     "@typescript-eslint/eslint-plugin": "^7.0.0",
diff --git a/packages/pg-connection-string/test/parse.js b/packages/pg-connection-string/test/parse.js
index 59f16a62e..9b37eebf9 100644
--- a/packages/pg-connection-string/test/parse.js
+++ b/packages/pg-connection-string/test/parse.js
@@ -1,13 +1,13 @@
 'use strict'
 
-var chai = require('chai')
+const chai = require('chai')
 chai.should()
 
-var parse = require('../').parse
+const parse = require('../').parse
 
 describe('parse', function () {
   it('using connection string in client constructor', function () {
-    var subject = parse('postgres://brian:pw@boom:381/lala')
+    const subject = parse('postgres://brian:pw@boom:381/lala')
     subject.user.should.equal('brian')
     subject.password.should.equal('pw')
     subject.host.should.equal('boom')
@@ -16,42 +16,42 @@ describe('parse', function () {
   })
 
   it('escape spaces if present', function () {
-    var subject = parse('postgres://localhost/post gres')
+    const subject = parse('postgres://localhost/post gres')
     subject.database.should.equal('post gres')
   })
 
   it('do not double escape spaces', function () {
-    var subject = parse('postgres://localhost/post%20gres')
+    const subject = parse('postgres://localhost/post%20gres')
     subject.database.should.equal('post gres')
   })
 
   it('initializing with unix domain socket', function () {
-    var subject = parse('/var/run/')
+    const subject = parse('/var/run/')
     subject.host.should.equal('/var/run/')
   })
 
   it('initializing with unix domain socket and a specific database, the simple way', function () {
-    var subject = parse('/var/run/ mydb')
+    const subject = parse('/var/run/ mydb')
     subject.host.should.equal('/var/run/')
     subject.database.should.equal('mydb')
   })
 
   it('initializing with unix domain socket, the health way', function () {
-    var subject = parse('socket:/some path/?db=my[db]&encoding=utf8')
+    const subject = parse('socket:/some path/?db=my[db]&encoding=utf8')
     subject.host.should.equal('/some path/')
     subject.database.should.equal('my[db]', 'must to be escaped and unescaped trough "my%5Bdb%5D"')
     subject.client_encoding.should.equal('utf8')
   })
 
   it('initializing with unix domain socket, the escaped health way', function () {
-    var subject = parse('socket:/some%20path/?db=my%2Bdb&encoding=utf8')
+    const subject = parse('socket:/some%20path/?db=my%2Bdb&encoding=utf8')
     subject.host.should.equal('/some path/')
     subject.database.should.equal('my+db')
     subject.client_encoding.should.equal('utf8')
   })
 
   it('initializing with unix domain socket, username and password', function () {
-    var subject = parse('socket://brian:pw@/var/run/?db=mydb')
+    const subject = parse('socket://brian:pw@/var/run/?db=mydb')
     subject.user.should.equal('brian')
     subject.password.should.equal('pw')
     subject.host.should.equal('/var/run/')
@@ -59,14 +59,14 @@ describe('parse', function () {
   })
 
   it('password contains  < and/or >  characters', function () {
-    var sourceConfig = {
+    const sourceConfig = {
       user: 'brian',
       password: 'hello<ther>e',
       host: 'localhost',
       port: 5432,
       database: 'postgres',
     }
-    var connectionString =
+    const connectionString =
       'postgres://' +
       sourceConfig.user +
       ':' +
@@ -77,19 +77,19 @@ describe('parse', function () {
       sourceConfig.port +
       '/' +
       sourceConfig.database
-    var subject = parse(connectionString)
+    const subject = parse(connectionString)
     subject.password.should.equal(sourceConfig.password)
   })
 
   it('password contains colons', function () {
-    var sourceConfig = {
+    const sourceConfig = {
       user: 'brian',
       password: 'hello:pass:world',
       host: 'localhost',
       port: 5432,
       database: 'postgres',
     }
-    var connectionString =
+    const connectionString =
       'postgres://' +
       sourceConfig.user +
       ':' +
@@ -100,21 +100,21 @@ describe('parse', function () {
       sourceConfig.port +
       '/' +
       sourceConfig.database
-    var subject = parse(connectionString)
+    const subject = parse(connectionString)
     subject.password.should.equal(sourceConfig.password)
   })
 
   it('username or password contains weird characters', function () {
-    var strang = 'pg://my f%irst name:is&%awesome!@localhost:9000'
-    var subject = parse(strang)
+    const strang = 'pg://my f%irst name:is&%awesome!@localhost:9000'
+    const subject = parse(strang)
     subject.user.should.equal('my f%irst name')
     subject.password.should.equal('is&%awesome!')
     subject.host.should.equal('localhost')
   })
 
   it('url is properly encoded', function () {
-    var encoded = 'pg://bi%25na%25%25ry%20:s%40f%23@localhost/%20u%2520rl'
-    var subject = parse(encoded)
+    const encoded = 'pg://bi%25na%25%25ry%20:s%40f%23@localhost/%20u%2520rl'
+    const subject = parse(encoded)
     subject.user.should.equal('bi%na%%ry ')
     subject.password.should.equal('s@f#')
     subject.host.should.equal('localhost')
@@ -122,24 +122,24 @@ describe('parse', function () {
   })
 
   it('relative url sets database', function () {
-    var relative = 'different_db_on_default_host'
-    var subject = parse(relative)
+    const relative = 'different_db_on_default_host'
+    const subject = parse(relative)
     subject.database.should.equal('different_db_on_default_host')
   })
 
   it('no pathname returns null database', function () {
-    var subject = parse('pg://myhost')
+    const subject = parse('pg://myhost')
     ;(subject.database === null).should.equal(true)
   })
 
   it('pathname of "/" returns null database', function () {
-    var subject = parse('pg://myhost/')
+    const subject = parse('pg://myhost/')
     subject.host.should.equal('myhost')
     ;(subject.database === null).should.equal(true)
   })
 
   it('configuration parameter host', function () {
-    var subject = parse('pg://user:pass@/dbname?host=/unix/socket')
+    const subject = parse('pg://user:pass@/dbname?host=/unix/socket')
     subject.user.should.equal('user')
     subject.password.should.equal('pass')
     subject.host.should.equal('/unix/socket')
@@ -147,13 +147,13 @@ describe('parse', function () {
   })
 
   it('configuration parameter host overrides url host', function () {
-    var subject = parse('pg://user:pass@localhost/dbname?host=/unix/socket')
+    const subject = parse('pg://user:pass@localhost/dbname?host=/unix/socket')
     subject.database.should.equal('dbname')
     subject.host.should.equal('/unix/socket')
   })
 
   it('url with encoded socket', function () {
-    var subject = parse('pg://user:pass@%2Funix%2Fsocket/dbname')
+    const subject = parse('pg://user:pass@%2Funix%2Fsocket/dbname')
     subject.user.should.equal('user')
     subject.password.should.equal('pass')
     subject.host.should.equal('/unix/socket')
@@ -161,7 +161,7 @@ describe('parse', function () {
   })
 
   it('url with real host and an encoded db name', function () {
-    var subject = parse('pg://user:pass@localhost/%2Fdbname')
+    const subject = parse('pg://user:pass@localhost/%2Fdbname')
     subject.user.should.equal('user')
     subject.password.should.equal('pass')
     subject.host.should.equal('localhost')
@@ -169,7 +169,7 @@ describe('parse', function () {
   })
 
   it('configuration parameter host treats encoded host as part of the db name', function () {
-    var subject = parse('pg://user:pass@%2Funix%2Fsocket/dbname?host=localhost')
+    const subject = parse('pg://user:pass@%2Funix%2Fsocket/dbname?host=localhost')
     subject.user.should.equal('user')
     subject.password.should.equal('pass')
     subject.host.should.equal('localhost')
@@ -177,150 +177,150 @@ describe('parse', function () {
   })
 
   it('configuration parameter application_name', function () {
-    var connectionString = 'pg:///?application_name=TheApp'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?application_name=TheApp'
+    const subject = parse(connectionString)
     subject.application_name.should.equal('TheApp')
   })
 
   it('configuration parameter fallback_application_name', function () {
-    var connectionString = 'pg:///?fallback_application_name=TheAppFallback'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?fallback_application_name=TheAppFallback'
+    const subject = parse(connectionString)
     subject.fallback_application_name.should.equal('TheAppFallback')
   })
 
   it('configuration parameter options', function () {
-    var connectionString = 'pg:///?options=-c geqo=off'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?options=-c geqo=off'
+    const subject = parse(connectionString)
     subject.options.should.equal('-c geqo=off')
   })
 
   it('configuration parameter ssl=true', function () {
-    var connectionString = 'pg:///?ssl=true'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?ssl=true'
+    const subject = parse(connectionString)
     subject.ssl.should.equal(true)
   })
 
   it('configuration parameter ssl=1', function () {
-    var connectionString = 'pg:///?ssl=1'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?ssl=1'
+    const subject = parse(connectionString)
     subject.ssl.should.equal(true)
   })
 
   it('configuration parameter ssl=0', function () {
-    var connectionString = 'pg:///?ssl=0'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?ssl=0'
+    const subject = parse(connectionString)
     subject.ssl.should.equal(false)
   })
 
   it('set ssl', function () {
-    var subject = parse('pg://myhost/db?ssl=1')
+    const subject = parse('pg://myhost/db?ssl=1')
     subject.ssl.should.equal(true)
   })
 
   it('configuration parameter sslcert=/path/to/cert', function () {
-    var connectionString = 'pg:///?sslcert=' + __dirname + '/example.cert'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?sslcert=' + __dirname + '/example.cert'
+    const subject = parse(connectionString)
     subject.ssl.should.eql({
       cert: 'example cert\n',
     })
   })
 
   it('configuration parameter sslkey=/path/to/key', function () {
-    var connectionString = 'pg:///?sslkey=' + __dirname + '/example.key'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?sslkey=' + __dirname + '/example.key'
+    const subject = parse(connectionString)
     subject.ssl.should.eql({
       key: 'example key\n',
     })
   })
 
   it('configuration parameter sslrootcert=/path/to/ca', function () {
-    var connectionString = 'pg:///?sslrootcert=' + __dirname + '/example.ca'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?sslrootcert=' + __dirname + '/example.ca'
+    const subject = parse(connectionString)
     subject.ssl.should.eql({
       ca: 'example ca\n',
     })
   })
 
   it('configuration parameter sslmode=no-verify', function () {
-    var connectionString = 'pg:///?sslmode=no-verify'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?sslmode=no-verify'
+    const subject = parse(connectionString)
     subject.ssl.should.eql({
       rejectUnauthorized: false,
     })
   })
 
   it('configuration parameter sslmode=disable', function () {
-    var connectionString = 'pg:///?sslmode=disable'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?sslmode=disable'
+    const subject = parse(connectionString)
     subject.ssl.should.eql(false)
   })
 
   it('configuration parameter sslmode=prefer', function () {
-    var connectionString = 'pg:///?sslmode=prefer'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?sslmode=prefer'
+    const subject = parse(connectionString)
     subject.ssl.should.eql({})
   })
 
   it('configuration parameter sslmode=require', function () {
-    var connectionString = 'pg:///?sslmode=require'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?sslmode=require'
+    const subject = parse(connectionString)
     subject.ssl.should.eql({})
   })
 
   it('configuration parameter sslmode=verify-ca', function () {
-    var connectionString = 'pg:///?sslmode=verify-ca'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?sslmode=verify-ca'
+    const subject = parse(connectionString)
     subject.ssl.should.eql({})
   })
 
   it('configuration parameter sslmode=verify-full', function () {
-    var connectionString = 'pg:///?sslmode=verify-full'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?sslmode=verify-full'
+    const subject = parse(connectionString)
     subject.ssl.should.eql({})
   })
 
   it('configuration parameter ssl=true and sslmode=require still work with sslrootcert=/path/to/ca', function () {
-    var connectionString = 'pg:///?ssl=true&sslrootcert=' + __dirname + '/example.ca&sslmode=require'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?ssl=true&sslrootcert=' + __dirname + '/example.ca&sslmode=require'
+    const subject = parse(connectionString)
     subject.ssl.should.eql({
       ca: 'example ca\n',
     })
   })
 
   it('allow other params like max, ...', function () {
-    var subject = parse('pg://myhost/db?max=18&min=4')
+    const subject = parse('pg://myhost/db?max=18&min=4')
     subject.max.should.equal('18')
     subject.min.should.equal('4')
   })
 
   it('configuration parameter keepalives', function () {
-    var connectionString = 'pg:///?keepalives=1'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?keepalives=1'
+    const subject = parse(connectionString)
     subject.keepalives.should.equal('1')
   })
 
   it('unknown configuration parameter is passed into client', function () {
-    var connectionString = 'pg:///?ThereIsNoSuchPostgresParameter=1234'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?ThereIsNoSuchPostgresParameter=1234'
+    const subject = parse(connectionString)
     subject.ThereIsNoSuchPostgresParameter.should.equal('1234')
   })
 
   it('do not override a config field with value from query string', function () {
-    var subject = parse('socket:/some path/?db=my[db]&encoding=utf8&client_encoding=bogus')
+    const subject = parse('socket:/some path/?db=my[db]&encoding=utf8&client_encoding=bogus')
     subject.host.should.equal('/some path/')
     subject.database.should.equal('my[db]', 'must to be escaped and unescaped through "my%5Bdb%5D"')
     subject.client_encoding.should.equal('utf8')
   })
 
   it('return last value of repeated parameter', function () {
-    var connectionString = 'pg:///?keepalives=1&keepalives=0'
-    var subject = parse(connectionString)
+    const connectionString = 'pg:///?keepalives=1&keepalives=0'
+    const subject = parse(connectionString)
     subject.keepalives.should.equal('0')
   })
 
   it('use the port specified in the query parameters', function () {
-    var connectionString = 'postgres:///?host=localhost&port=1234'
-    var subject = parse(connectionString)
+    const connectionString = 'postgres:///?host=localhost&port=1234'
+    const subject = parse(connectionString)
     subject.port.should.equal('1234')
   })
 })
diff --git a/packages/pg-native/bench/index.js b/packages/pg-native/bench/index.js
index 05dbc949b..06d5fb59b 100644
--- a/packages/pg-native/bench/index.js
+++ b/packages/pg-native/bench/index.js
@@ -1,10 +1,10 @@
-var pg = require('pg').native
-var Native = require('../')
+const pg = require('pg').native
+const Native = require('../')
 
-var warmup = function (fn, cb) {
-  var count = 0
-  var max = 10
-  var run = function (err) {
+const warmup = function (fn, cb) {
+  let count = 0
+  const max = 10
+  const run = function (err) {
     if (err) return cb(err)
 
     if (max >= count++) {
@@ -16,27 +16,27 @@ var warmup = function (fn, cb) {
   run()
 }
 
-var native = Native()
+const native = Native()
 native.connectSync()
 
-var queryText = 'SELECT generate_series(0, 1000)'
-var client = new pg.Client()
+const queryText = 'SELECT generate_series(0, 1000)'
+const client = new pg.Client()
 client.connect(function () {
-  var pure = function (cb) {
+  const pure = function (cb) {
     client.query(queryText, function (err) {
       if (err) throw err
       cb(err)
     })
   }
-  var nativeQuery = function (cb) {
+  const nativeQuery = function (cb) {
     native.query(queryText, function (err) {
       if (err) throw err
       cb(err)
     })
   }
 
-  var run = function () {
-    var start = Date.now()
+  const run = function () {
+    let start = Date.now()
     warmup(pure, function () {
       console.log('pure done', Date.now() - start)
       start = Date.now()
diff --git a/packages/pg-native/bench/leaks.js b/packages/pg-native/bench/leaks.js
index 57fe36da2..72fb8bcef 100644
--- a/packages/pg-native/bench/leaks.js
+++ b/packages/pg-native/bench/leaks.js
@@ -1,29 +1,29 @@
-var Client = require('../')
-var async = require('async')
+const Client = require('../')
+const async = require('async')
 
-var loop = function () {
-  var client = new Client()
+const loop = function () {
+  const client = new Client()
 
-  var connect = function (cb) {
+  const connect = function (cb) {
     client.connect(cb)
   }
 
-  var simpleQuery = function (cb) {
+  const simpleQuery = function (cb) {
     client.query('SELECT NOW()', cb)
   }
 
-  var paramsQuery = function (cb) {
+  const paramsQuery = function (cb) {
     client.query('SELECT $1::text as name', ['Brian'], cb)
   }
 
-  var prepared = function (cb) {
+  const prepared = function (cb) {
     client.prepare('test', 'SELECT $1::text as name', 1, function (err) {
       if (err) return cb(err)
       client.execute('test', ['Brian'], cb)
     })
   }
 
-  var sync = function (cb) {
+  const sync = function (cb) {
     client.querySync('SELECT NOW()')
     client.querySync('SELECT $1::text as name', ['Brian'])
     client.prepareSync('boom', 'SELECT $1::text as name', 1)
@@ -31,13 +31,13 @@ var loop = function () {
     setImmediate(cb)
   }
 
-  var end = function (cb) {
+  const end = function (cb) {
     client.end(cb)
   }
 
-  var ops = [connect, simpleQuery, paramsQuery, prepared, sync, end]
+  const ops = [connect, simpleQuery, paramsQuery, prepared, sync, end]
 
-  var start = Date.now()
+  const start = Date.now()
   async.series(ops, function (err) {
     if (err) throw err
     console.log(Date.now() - start)
diff --git a/packages/pg-native/index.js b/packages/pg-native/index.js
index a3c3f070b..0cc2f646d 100644
--- a/packages/pg-native/index.js
+++ b/packages/pg-native/index.js
@@ -1,12 +1,12 @@
-var Libpq = require('libpq')
-var EventEmitter = require('events').EventEmitter
-var util = require('util')
-var assert = require('assert')
-var types = require('pg-types')
-var buildResult = require('./lib/build-result')
-var CopyStream = require('./lib/copy-stream')
-
-var Client = (module.exports = function (config) {
+const Libpq = require('libpq')
+const EventEmitter = require('events').EventEmitter
+const util = require('util')
+const assert = require('assert')
+const types = require('pg-types')
+const buildResult = require('./lib/build-result')
+const CopyStream = require('./lib/copy-stream')
+
+const Client = (module.exports = function (config) {
   if (!(this instanceof Client)) {
     return new Client(config)
   }
@@ -51,7 +51,7 @@ Client.prototype.connectSync = function (params) {
 }
 
 Client.prototype.query = function (text, values, cb) {
-  var queryFn
+  let queryFn
 
   if (typeof values === 'function') {
     cb = values
@@ -67,7 +67,7 @@ Client.prototype.query = function (text, values, cb) {
     }
   }
 
-  var self = this
+  const self = this
 
   self._dispatchQuery(self.pq, queryFn, function (err) {
     if (err) return cb(err)
@@ -77,8 +77,8 @@ Client.prototype.query = function (text, values, cb) {
 }
 
 Client.prototype.prepare = function (statementName, text, nParams, cb) {
-  var self = this
-  var fn = function () {
+  const self = this
+  const fn = function () {
     return self.pq.sendPrepare(statementName, text, nParams)
   }
 
@@ -89,9 +89,9 @@ Client.prototype.prepare = function (statementName, text, nParams, cb) {
 }
 
 Client.prototype.execute = function (statementName, parameters, cb) {
-  var self = this
+  const self = this
 
-  var fn = function () {
+  const fn = function () {
     return self.pq.sendQueryPrepared(statementName, parameters)
   }
 
@@ -111,7 +111,7 @@ Client.prototype.getCopyStream = function () {
 Client.prototype.cancel = function (cb) {
   assert(cb, 'Callback is required')
   // result is either true or a string containing an error
-  var result = this.pq.cancel()
+  const result = this.pq.cancel()
   return setImmediate(function () {
     cb(result === true ? undefined : new Error(result))
   })
@@ -158,7 +158,7 @@ Client.prototype.end = function (cb) {
 }
 
 Client.prototype._readError = function (message) {
-  var err = new Error(message || this.pq.errorMessage())
+  const err = new Error(message || this.pq.errorMessage())
   this.emit('error', err)
 }
 
@@ -174,7 +174,7 @@ Client.prototype._consumeQueryResults = function (pq) {
 }
 
 Client.prototype._emitResult = function (pq) {
-  var status = pq.resultStatus()
+  const status = pq.resultStatus()
   switch (status) {
     case 'PGRES_FATAL_ERROR':
       this._queryError = new Error(this.pq.resultErrorMessage())
@@ -201,7 +201,7 @@ Client.prototype._emitResult = function (pq) {
 
 // called when libpq is readable
 Client.prototype._read = function () {
-  var pq = this.pq
+  const pq = this.pq
   // read waiting data from the socket
   // e.g. clear the pending 'select'
   if (!pq.consumeInput()) {
@@ -236,7 +236,7 @@ Client.prototype._read = function () {
 
   this.emit('readyForQuery')
 
-  var notice = this.pq.notifies()
+  let notice = this.pq.notifies()
   while (notice) {
     this.emit('notification', notice)
     notice = this.pq.notifies()
@@ -252,8 +252,8 @@ Client.prototype._startReading = function () {
   this.pq.startReader()
 }
 
-var throwIfError = function (pq) {
-  var err = pq.resultErrorMessage() || pq.errorMessage()
+const throwIfError = function (pq) {
+  const err = pq.resultErrorMessage() || pq.errorMessage()
   if (err) {
     throw new Error(err)
   }
@@ -266,7 +266,7 @@ Client.prototype._awaitResult = function (cb) {
 
 // wait for the writable socket to drain
 Client.prototype._waitForDrain = function (pq, cb) {
-  var res = pq.flush()
+  const res = pq.flush()
   // res of 0 is success
   if (res === 0) return cb()
 
@@ -275,7 +275,7 @@ Client.prototype._waitForDrain = function (pq, cb) {
 
   // otherwise outgoing message didn't flush to socket
   // wait for it to flush and try again
-  var self = this
+  const self = this
   // you cannot read & write on a socket at the same time
   return pq.writable(function () {
     self._waitForDrain(pq, cb)
@@ -286,9 +286,9 @@ Client.prototype._waitForDrain = function (pq, cb) {
 // finish writing query text to the socket
 Client.prototype._dispatchQuery = function (pq, fn, cb) {
   this._stopReading()
-  var success = pq.setNonBlocking(true)
+  const success = pq.setNonBlocking(true)
   if (!success) return cb(new Error('Unable to set non-blocking to true'))
-  var sent = fn()
+  const sent = fn()
   if (!sent) return cb(new Error(pq.errorMessage() || 'Something went wrong dispatching the query'))
   this._waitForDrain(pq, cb)
 }
diff --git a/packages/pg-native/lib/build-result.js b/packages/pg-native/lib/build-result.js
index 38408a608..7d313372b 100644
--- a/packages/pg-native/lib/build-result.js
+++ b/packages/pg-native/lib/build-result.js
@@ -18,7 +18,7 @@ class Result {
 
   consumeFields(pq) {
     const nfields = pq.nfields()
-    for (var x = 0; x < nfields; x++) {
+    for (let x = 0; x < nfields; x++) {
       this.fields.push({
         name: pq.fname(x),
         dataTypeID: pq.ftype(x),
@@ -28,7 +28,7 @@ class Result {
 
   consumeRows(pq) {
     const tupleCount = pq.ntuples()
-    for (var i = 0; i < tupleCount; i++) {
+    for (let i = 0; i < tupleCount; i++) {
       const row = this._arrayMode ? this.consumeRowAsArray(pq, i) : this.consumeRowAsObject(pq, i)
       this.rows.push(row)
     }
@@ -36,7 +36,7 @@ class Result {
 
   consumeRowAsObject(pq, rowIndex) {
     const row = {}
-    for (var j = 0; j < this.fields.length; j++) {
+    for (let j = 0; j < this.fields.length; j++) {
       const value = this.readValue(pq, rowIndex, j)
       row[this.fields[j].name] = value
     }
@@ -45,7 +45,7 @@ class Result {
 
   consumeRowAsArray(pq, rowIndex) {
     const row = []
-    for (var j = 0; j < this.fields.length; j++) {
+    for (let j = 0; j < this.fields.length; j++) {
       const value = this.readValue(pq, rowIndex, j)
       row.push(value)
     }
@@ -53,7 +53,7 @@ class Result {
   }
 
   readValue(pq, rowIndex, colIndex) {
-    var rawValue = pq.getvalue(rowIndex, colIndex)
+    const rawValue = pq.getvalue(rowIndex, colIndex)
     if (rawValue === '') {
       if (pq.getisnull(rowIndex, colIndex)) {
         return null
diff --git a/packages/pg-native/lib/copy-stream.js b/packages/pg-native/lib/copy-stream.js
index 13b455383..94ae4f7e5 100644
--- a/packages/pg-native/lib/copy-stream.js
+++ b/packages/pg-native/lib/copy-stream.js
@@ -1,8 +1,8 @@
-var Duplex = require('stream').Duplex
-var Writable = require('stream').Writable
-var util = require('util')
+const Duplex = require('stream').Duplex
+const Writable = require('stream').Writable
+const util = require('util')
 
-var CopyStream = (module.exports = function (pq, options) {
+const CopyStream = (module.exports = function (pq, options) {
   Duplex.call(this, options)
   this.pq = pq
   this._reading = false
@@ -12,7 +12,7 @@ util.inherits(CopyStream, Duplex)
 
 // writer methods
 CopyStream.prototype._write = function (chunk, encoding, cb) {
-  var result = this.pq.putCopyData(chunk)
+  const result = this.pq.putCopyData(chunk)
 
   // sent successfully
   if (result === 1) return cb()
@@ -21,22 +21,22 @@ CopyStream.prototype._write = function (chunk, encoding, cb) {
   if (result === -1) return cb(new Error(this.pq.errorMessage()))
 
   // command would block. wait for writable and call again.
-  var self = this
+  const self = this
   this.pq.writable(function () {
     self._write(chunk, encoding, cb)
   })
 }
 
 CopyStream.prototype.end = function () {
-  var args = Array.prototype.slice.call(arguments, 0)
-  var self = this
+  const args = Array.prototype.slice.call(arguments, 0)
+  const self = this
 
-  var callback = args.pop()
+  const callback = args.pop()
 
   if (args.length) {
     this.write(args[0])
   }
-  var result = this.pq.putCopyEnd()
+  const result = this.pq.putCopyEnd()
 
   // sent successfully
   if (result === 1) {
@@ -55,7 +55,7 @@ CopyStream.prototype.end = function () {
 
   // error
   if (result === -1) {
-    var err = new Error(this.pq.errorMessage())
+    const err = new Error(this.pq.errorMessage())
     return this.emit('error', err)
   }
 
@@ -70,7 +70,7 @@ CopyStream.prototype.end = function () {
 
 // reader methods
 CopyStream.prototype._consumeBuffer = function (cb) {
-  var result = this.pq.getCopyData(true)
+  const result = this.pq.getCopyData(true)
   if (result instanceof Buffer) {
     return setImmediate(function () {
       cb(null, result)
@@ -81,7 +81,7 @@ CopyStream.prototype._consumeBuffer = function (cb) {
     return cb(null, null)
   }
   if (result === 0) {
-    var self = this
+    const self = this
     this.pq.once('readable', function () {
       self.pq.stopReader()
       self.pq.consumeInput()
@@ -96,7 +96,7 @@ CopyStream.prototype._read = function (size) {
   if (this._reading) return
   this._reading = true
   // console.log('read begin');
-  var self = this
+  const self = this
   this._consumeBuffer(function (err, buffer) {
     self._reading = false
     if (err) {
@@ -110,18 +110,18 @@ CopyStream.prototype._read = function (size) {
   })
 }
 
-var consumeResults = function (pq, cb) {
-  var cleanup = function () {
+const consumeResults = function (pq, cb) {
+  const cleanup = function () {
     pq.removeListener('readable', onReadable)
     pq.stopReader()
   }
 
-  var readError = function (message) {
+  const readError = function (message) {
     cleanup()
     return cb(new Error(message || pq.errorMessage()))
   }
 
-  var onReadable = function () {
+  const onReadable = function () {
     // read waiting data from the socket
     // e.g. clear the pending 'select'
     if (!pq.consumeInput()) {
diff --git a/packages/pg-native/test/array-mode.js b/packages/pg-native/test/array-mode.js
index c79d471d2..0e6978a0a 100644
--- a/packages/pg-native/test/array-mode.js
+++ b/packages/pg-native/test/array-mode.js
@@ -1,16 +1,16 @@
-var Client = require('../')
-var assert = require('assert')
+const Client = require('../')
+const assert = require('assert')
 
 describe('client with arrayMode', function () {
   it('returns result as array', function (done) {
-    var client = new Client({ arrayMode: true })
+    const client = new Client({ arrayMode: true })
     client.connectSync()
     client.querySync('CREATE TEMP TABLE blah(name TEXT)')
     client.querySync('INSERT INTO blah (name) VALUES ($1)', ['brian'])
     client.querySync('INSERT INTO blah (name) VALUES ($1)', ['aaron'])
-    var rows = client.querySync('SELECT * FROM blah')
+    const rows = client.querySync('SELECT * FROM blah')
     assert.equal(rows.length, 2)
-    var row = rows[0]
+    const row = rows[0]
     assert.equal(row.length, 1)
     assert.equal(row[0], 'brian')
     assert.equal(rows[1][0], 'aaron')
diff --git a/packages/pg-native/test/async-workflow.js b/packages/pg-native/test/async-workflow.js
index 975c5a97f..e86774b87 100644
--- a/packages/pg-native/test/async-workflow.js
+++ b/packages/pg-native/test/async-workflow.js
@@ -1,7 +1,7 @@
-var Client = require('../')
-var ok = require('okay')
-var assert = require('assert')
-var concat = require('concat-stream')
+const Client = require('../')
+const ok = require('okay')
+const assert = require('assert')
+const concat = require('concat-stream')
 
 describe('async workflow', function () {
   before(function (done) {
@@ -9,7 +9,7 @@ describe('async workflow', function () {
     this.client.connect(done)
   })
 
-  var echoParams = function (params, cb) {
+  const echoParams = function (params, cb) {
     this.client.query(
       'SELECT $1::text as first, $2::text as second',
       params,
@@ -20,20 +20,20 @@ describe('async workflow', function () {
     )
   }
 
-  var checkParams = function (params, rows) {
+  const checkParams = function (params, rows) {
     assert.equal(rows.length, 1)
     assert.equal(rows[0].first, params[0])
     assert.equal(rows[0].second, params[1])
   }
 
   it('sends async query', function (done) {
-    var params = ['one', 'two']
+    const params = ['one', 'two']
     echoParams.call(this, params, done)
   })
 
   it('sends multiple async queries', function (done) {
-    var self = this
-    var params = ['bang', 'boom']
+    const self = this
+    const params = ['bang', 'boom']
     echoParams.call(
       this,
       params,
@@ -44,13 +44,13 @@ describe('async workflow', function () {
   })
 
   it('sends an async query, copies in, copies out, and sends another query', function (done) {
-    var self = this
+    const self = this
     this.client.querySync('CREATE TEMP TABLE test(name text, age int)')
     this.client.query(
       "INSERT INTO test(name, age) VALUES('brian', 32)",
       ok(done, function () {
         self.client.querySync('COPY test FROM stdin')
-        var input = self.client.getCopyStream()
+        const input = self.client.getCopyStream()
         input.write(Buffer.from('Aaron\t30\n', 'utf8'))
         input.end(function () {
           self.client.query(
@@ -60,7 +60,7 @@ describe('async workflow', function () {
               self.client.query(
                 'COPY test TO stdout',
                 ok(done, function () {
-                  var output = self.client.getCopyStream()
+                  const output = self.client.getCopyStream()
 
                   // pump the stream
                   output.read()
diff --git a/packages/pg-native/test/cancel.js b/packages/pg-native/test/cancel.js
index 80b1494df..8360c37f3 100644
--- a/packages/pg-native/test/cancel.js
+++ b/packages/pg-native/test/cancel.js
@@ -1,9 +1,9 @@
-var Client = require('../')
-var assert = require('assert')
+const Client = require('../')
+const assert = require('assert')
 
 describe('cancel query', function () {
   it('works', function (done) {
-    var client = new Client()
+    const client = new Client()
     client.connectSync()
     client.query('SELECT pg_sleep(1000);', function (err) {
       assert(err instanceof Error)
@@ -17,7 +17,7 @@ describe('cancel query', function () {
   })
 
   it('does not raise error if no active query', function (done) {
-    var client = new Client()
+    const client = new Client()
     client.connectSync()
     client.cancel(function (err) {
       assert.ifError(err)
diff --git a/packages/pg-native/test/connection-errors.js b/packages/pg-native/test/connection-errors.js
index e02f2025b..ed836da2d 100644
--- a/packages/pg-native/test/connection-errors.js
+++ b/packages/pg-native/test/connection-errors.js
@@ -1,11 +1,11 @@
 'use strict'
 
-var Client = require('../')
-var assert = require('assert')
+const Client = require('../')
+const assert = require('assert')
 
 describe('connection errors', function () {
   it('raise error events', function (done) {
-    var client = new Client()
+    const client = new Client()
     client.connectSync()
     client.query('SELECT pg_terminate_backend(pg_backend_pid())', assert.fail)
     client.on('error', function (err) {
diff --git a/packages/pg-native/test/connection.js b/packages/pg-native/test/connection.js
index af81ffda9..0c7059ea4 100644
--- a/packages/pg-native/test/connection.js
+++ b/packages/pg-native/test/connection.js
@@ -1,9 +1,9 @@
-var Client = require('../')
-var assert = require('assert')
+const Client = require('../')
+const assert = require('assert')
 
 describe('connection error', function () {
   it('doesnt segfault', function (done) {
-    var client = new Client()
+    const client = new Client()
     client.connect('asldgsdgasgdasdg', function (err) {
       assert(err)
       // calling error on a closed client was segfaulting
@@ -15,7 +15,7 @@ describe('connection error', function () {
 
 describe('reading while not connected', function () {
   it('does not seg fault but does throw execption', function () {
-    var client = new Client()
+    const client = new Client()
     assert.throws(function () {
       client.on('notification', function (msg) {})
     })
diff --git a/packages/pg-native/test/copy-from.js b/packages/pg-native/test/copy-from.js
index 87501a957..37c64b7cd 100644
--- a/packages/pg-native/test/copy-from.js
+++ b/packages/pg-native/test/copy-from.js
@@ -1,5 +1,5 @@
-var assert = require('assert')
-var Client = require('../')
+const assert = require('assert')
+const Client = require('../')
 
 describe('COPY FROM', function () {
   before(function (done) {
@@ -12,17 +12,17 @@ describe('COPY FROM', function () {
   })
 
   it('works', function (done) {
-    var client = this.client
+    const client = this.client
     this.client.querySync('CREATE TEMP TABLE blah(name text, age int)')
     this.client.querySync('COPY blah FROM stdin')
-    var stream = this.client.getCopyStream()
+    const stream = this.client.getCopyStream()
     stream.write(Buffer.from('Brian\t32\n', 'utf8'))
     stream.write(Buffer.from('Aaron\t30\n', 'utf8'))
     stream.write(Buffer.from('Shelley\t28\n', 'utf8'))
     stream.end()
 
     stream.once('finish', function () {
-      var rows = client.querySync('SELECT COUNT(*) FROM blah')
+      const rows = client.querySync('SELECT COUNT(*) FROM blah')
       assert.equal(rows.length, 1)
       assert.equal(rows[0].count, 3)
       done()
@@ -30,14 +30,14 @@ describe('COPY FROM', function () {
   })
 
   it('works with a callback passed to end', function (done) {
-    var client = this.client
+    const client = this.client
     this.client.querySync('CREATE TEMP TABLE boom(name text, age int)')
     this.client.querySync('COPY boom FROM stdin')
-    var stream = this.client.getCopyStream()
+    const stream = this.client.getCopyStream()
     stream.write(Buffer.from('Brian\t32\n', 'utf8'))
     stream.write(Buffer.from('Aaron\t30\n', 'utf8'), function () {
       stream.end(Buffer.from('Shelley\t28\n', 'utf8'), function () {
-        var rows = client.querySync('SELECT COUNT(*) FROM boom')
+        const rows = client.querySync('SELECT COUNT(*) FROM boom')
         assert.equal(rows.length, 1)
         assert.equal(rows[0].count, 3)
         done()
diff --git a/packages/pg-native/test/copy-to.js b/packages/pg-native/test/copy-to.js
index 28e062556..7322735db 100644
--- a/packages/pg-native/test/copy-to.js
+++ b/packages/pg-native/test/copy-to.js
@@ -1,7 +1,7 @@
-var assert = require('assert')
-var Client = require('../')
-var concat = require('concat-stream')
-var _ = require('lodash')
+const assert = require('assert')
+const Client = require('../')
+const concat = require('concat-stream')
+const _ = require('lodash')
 
 describe('COPY TO', function () {
   before(function (done) {
@@ -14,18 +14,18 @@ describe('COPY TO', function () {
   })
 
   it('works - basic check', function (done) {
-    var limit = 1000
-    var qText = 'COPY (SELECT * FROM generate_series(0, ' + (limit - 1) + ')) TO stdout'
-    var self = this
+    const limit = 1000
+    const qText = 'COPY (SELECT * FROM generate_series(0, ' + (limit - 1) + ')) TO stdout'
+    const self = this
     this.client.query(qText, function (err) {
       if (err) return done(err)
-      var stream = self.client.getCopyStream()
+      const stream = self.client.getCopyStream()
       // pump the stream for node v0.11.x
       stream.read()
       stream.pipe(
         concat(function (buff) {
-          var res = buff.toString('utf8')
-          var expected = _.range(0, limit).join('\n') + '\n'
+          const res = buff.toString('utf8')
+          const expected = _.range(0, limit).join('\n') + '\n'
           assert.equal(res, expected)
           done()
         })
diff --git a/packages/pg-native/test/custom-types.js b/packages/pg-native/test/custom-types.js
index 4930c85ae..329ff63af 100644
--- a/packages/pg-native/test/custom-types.js
+++ b/packages/pg-native/test/custom-types.js
@@ -1,10 +1,10 @@
-var Client = require('../')
-var ok = require('okay')
-var assert = require('assert')
+const Client = require('../')
+const ok = require('okay')
+const assert = require('assert')
 
 describe('Custom type parser', function () {
   it('is used by client', function (done) {
-    var client = new Client({
+    const client = new Client({
       types: {
         getTypeParser: function () {
           return function () {
@@ -14,7 +14,7 @@ describe('Custom type parser', function () {
       },
     })
     client.connectSync()
-    var rows = client.querySync('SELECT NOW() AS when')
+    const rows = client.querySync('SELECT NOW() AS when')
     assert.equal(rows[0].when, 'blah')
     client.query(
       'SELECT NOW() as when',
diff --git a/packages/pg-native/test/domains.js b/packages/pg-native/test/domains.js
index 90ae4d58e..2deadab1f 100644
--- a/packages/pg-native/test/domains.js
+++ b/packages/pg-native/test/domains.js
@@ -1,7 +1,7 @@
-var Client = require('../')
-var assert = require('assert')
+const Client = require('../')
+const assert = require('assert')
 
-var checkDomain = function (domain, when) {
+const checkDomain = function (domain, when) {
   assert(process.domain, 'Domain was lost after ' + when)
   assert.strictEqual(process.domain, domain, 'Domain switched after ' + when)
 }
@@ -10,7 +10,7 @@ describe('domains', function () {
   it('remains bound after a query', function (done) {
     var domain = require('domain').create() // eslint-disable-line
     domain.run(function () {
-      var client = new Client()
+      const client = new Client()
       client.connect(function () {
         checkDomain(domain, 'connection')
         client.query('SELECT NOW()', function () {
diff --git a/packages/pg-native/test/empty-query.js b/packages/pg-native/test/empty-query.js
index d8ec5611f..aa3f05a0d 100644
--- a/packages/pg-native/test/empty-query.js
+++ b/packages/pg-native/test/empty-query.js
@@ -1,5 +1,5 @@
-var Client = require('../')
-var assert = require('assert')
+const Client = require('../')
+const assert = require('assert')
 
 describe('empty query', () => {
   it('has field metadata in result', (done) => {
diff --git a/packages/pg-native/test/huge-query.js b/packages/pg-native/test/huge-query.js
index d3bf5cda2..838a23823 100644
--- a/packages/pg-native/test/huge-query.js
+++ b/packages/pg-native/test/huge-query.js
@@ -1,5 +1,5 @@
-var Client = require('../')
-var assert = require('assert')
+const Client = require('../')
+const assert = require('assert')
 
 describe('huge async query', function () {
   before(function (done) {
@@ -12,12 +12,12 @@ describe('huge async query', function () {
   })
 
   it('works', function (done) {
-    var params = ['']
-    var len = 100000
-    for (var i = 0; i < len; i++) {
+    const params = ['']
+    const len = 100000
+    for (let i = 0; i < len; i++) {
       params[0] += 'A'
     }
-    var qText = "SELECT '" + params[0] + "'::text as my_text"
+    const qText = "SELECT '" + params[0] + "'::text as my_text"
     this.client.query(qText, function (err, rows) {
       if (err) return done(err)
       assert.equal(rows[0].my_text.length, len)
diff --git a/packages/pg-native/test/index.js b/packages/pg-native/test/index.js
index 1ef15b09f..6770fe143 100644
--- a/packages/pg-native/test/index.js
+++ b/packages/pg-native/test/index.js
@@ -1,5 +1,5 @@
-var Client = require('../')
-var assert = require('assert')
+const Client = require('../')
+const assert = require('assert')
 
 describe('connection', function () {
   it('works', function (done) {
@@ -24,7 +24,7 @@ describe('connectSync', function () {
   })
 
   it('works with args', function () {
-    var args = 'host=' + (process.env.PGHOST || 'localhost')
+    const args = 'host=' + (process.env.PGHOST || 'localhost')
     Client().connectSync(args)
   })
 
diff --git a/packages/pg-native/test/load.js b/packages/pg-native/test/load.js
index 039ea7d06..886be5d24 100644
--- a/packages/pg-native/test/load.js
+++ b/packages/pg-native/test/load.js
@@ -1,11 +1,11 @@
-var Client = require('../')
-var async = require('async')
-var ok = require('okay')
+const Client = require('../')
+const async = require('async')
+const ok = require('okay')
 
-var execute = function (x, done) {
-  var client = new Client()
+const execute = function (x, done) {
+  const client = new Client()
   client.connectSync()
-  var query = function (n, cb) {
+  const query = function (n, cb) {
     client.query('SELECT $1::int as num', [n], function (err) {
       cb(err)
     })
diff --git a/packages/pg-native/test/many-connections.js b/packages/pg-native/test/many-connections.js
index fe32ede16..b1ed9fd47 100644
--- a/packages/pg-native/test/many-connections.js
+++ b/packages/pg-native/test/many-connections.js
@@ -1,16 +1,16 @@
-var Client = require('../')
-var async = require('async')
-var ok = require('okay')
-var bytes = require('crypto').pseudoRandomBytes
+const Client = require('../')
+const async = require('async')
+const ok = require('okay')
+const bytes = require('crypto').pseudoRandomBytes
 
 describe('many connections', function () {
   describe('async', function () {
-    var test = function (count, times) {
+    const test = function (count, times) {
       it(`connecting ${count} clients ${times} times`, function (done) {
         this.timeout(200000)
 
-        var connectClient = function (n, cb) {
-          var client = new Client()
+        const connectClient = function (n, cb) {
+          const client = new Client()
           client.connect(
             ok(cb, function () {
               bytes(
@@ -29,7 +29,7 @@ describe('many connections', function () {
           )
         }
 
-        var run = function (n, cb) {
+        const run = function (n, cb) {
           async.times(count, connectClient, cb)
         }
 
diff --git a/packages/pg-native/test/many-errors.js b/packages/pg-native/test/many-errors.js
index f8958f54b..243e6d491 100644
--- a/packages/pg-native/test/many-errors.js
+++ b/packages/pg-native/test/many-errors.js
@@ -1,14 +1,14 @@
-var Client = require('../')
-var async = require('async')
-var assert = require('assert')
+const Client = require('../')
+const async = require('async')
+const assert = require('assert')
 
 describe('many errors', function () {
   it('functions properly without segfault', function (done) {
-    var throwError = function (n, cb) {
-      var client = new Client()
+    const throwError = function (n, cb) {
+      const client = new Client()
       client.connectSync()
 
-      var doIt = function (n, cb) {
+      const doIt = function (n, cb) {
         client.query('select asdfiasdf', function (err) {
           assert(err, 'bad query should emit an error')
           cb(null)
diff --git a/packages/pg-native/test/multiple-queries.js b/packages/pg-native/test/multiple-queries.js
index ea67defed..438215ff3 100644
--- a/packages/pg-native/test/multiple-queries.js
+++ b/packages/pg-native/test/multiple-queries.js
@@ -1,5 +1,5 @@
-var Client = require('../')
-var assert = require('assert')
+const Client = require('../')
+const assert = require('assert')
 
 describe('multiple commands in a single query', function () {
   before(function (done) {
@@ -22,7 +22,7 @@ describe('multiple commands in a single query', function () {
   })
 
   it('inserts and reads at once', function (done) {
-    var txt = 'CREATE TEMP TABLE boom(age int);'
+    let txt = 'CREATE TEMP TABLE boom(age int);'
     txt += 'INSERT INTO boom(age) VALUES(10);'
     txt += 'SELECT * FROM boom;'
     this.client.query(txt, function (err, rows, results) {
diff --git a/packages/pg-native/test/multiple-statement-results.js b/packages/pg-native/test/multiple-statement-results.js
index ae0f9bafb..8c0a8574e 100644
--- a/packages/pg-native/test/multiple-statement-results.js
+++ b/packages/pg-native/test/multiple-statement-results.js
@@ -1,5 +1,5 @@
-var Client = require('../')
-var assert = require('assert')
+const Client = require('../')
+const assert = require('assert')
 
 describe('multiple statements', () => {
   before(() => {
diff --git a/packages/pg-native/test/notify.js b/packages/pg-native/test/notify.js
index 769faf39a..6fe7a7072 100644
--- a/packages/pg-native/test/notify.js
+++ b/packages/pg-native/test/notify.js
@@ -1,8 +1,8 @@
-var Client = require('../')
-var ok = require('okay')
+const Client = require('../')
+const ok = require('okay')
 
-var notify = function (channel, payload) {
-  var client = new Client()
+const notify = function (channel, payload) {
+  const client = new Client()
   client.connectSync()
   client.querySync('NOTIFY ' + channel + ", '" + payload + "'")
   client.end()
@@ -10,12 +10,12 @@ var notify = function (channel, payload) {
 
 describe('simple LISTEN/NOTIFY', function () {
   before(function (done) {
-    var client = (this.client = new Client())
+    const client = (this.client = new Client())
     client.connect(done)
   })
 
   it('works', function (done) {
-    var client = this.client
+    const client = this.client
     client.querySync('LISTEN boom')
     client.on('notification', function (msg) {
       done()
@@ -31,14 +31,14 @@ describe('simple LISTEN/NOTIFY', function () {
 if (!process.env.TRAVIS_CI) {
   describe('async LISTEN/NOTIFY', function () {
     before(function (done) {
-      var client = (this.client = new Client())
+      const client = (this.client = new Client())
       client.connect(done)
     })
 
     it('works', function (done) {
-      var client = this.client
-      var count = 0
-      var check = function () {
+      const client = this.client
+      let count = 0
+      const check = function () {
         count++
         if (count >= 2) return done()
       }
diff --git a/packages/pg-native/test/prepare.js b/packages/pg-native/test/prepare.js
index bae3fb34c..60ec32045 100644
--- a/packages/pg-native/test/prepare.js
+++ b/packages/pg-native/test/prepare.js
@@ -1,13 +1,13 @@
-var Client = require('../')
-var ok = require('okay')
-var async = require('async')
+const Client = require('../')
+const ok = require('okay')
+const async = require('async')
 
 describe('async prepare', function () {
-  var run = function (n, cb) {
-    var client = new Client()
+  const run = function (n, cb) {
+    const client = new Client()
     client.connectSync()
 
-    var exec = function (x, done) {
+    const exec = function (x, done) {
       client.prepare('get_now' + x, 'SELECT NOW()', 0, done)
     }
 
@@ -20,7 +20,7 @@ describe('async prepare', function () {
     )
   }
 
-  var t = function (n) {
+  const t = function (n) {
     it('works for ' + n + ' clients', function (done) {
       async.times(n, run, function (err) {
         done(err)
@@ -28,17 +28,17 @@ describe('async prepare', function () {
     })
   }
 
-  for (var i = 0; i < 10; i++) {
+  for (let i = 0; i < 10; i++) {
     t(i)
   }
 })
 
 describe('async execute', function () {
-  var run = function (n, cb) {
-    var client = new Client()
+  const run = function (n, cb) {
+    const client = new Client()
     client.connectSync()
     client.prepareSync('get_now', 'SELECT NOW()', 0)
-    var exec = function (x, cb) {
+    const exec = function (x, cb) {
       client.execute('get_now', [], cb)
     }
     async.timesSeries(
@@ -50,7 +50,7 @@ describe('async execute', function () {
     )
   }
 
-  var t = function (n) {
+  const t = function (n) {
     it('works for ' + n + ' clients', function (done) {
       async.times(n, run, function (err) {
         done(err)
@@ -58,7 +58,7 @@ describe('async execute', function () {
     })
   }
 
-  for (var i = 0; i < 10; i++) {
+  for (let i = 0; i < 10; i++) {
     t(i)
   }
 })
diff --git a/packages/pg-native/test/query-async.js b/packages/pg-native/test/query-async.js
index 9e2d05258..5e6cd17b2 100644
--- a/packages/pg-native/test/query-async.js
+++ b/packages/pg-native/test/query-async.js
@@ -1,7 +1,7 @@
-var Client = require('../')
-var assert = require('assert')
-var async = require('async')
-var ok = require('okay')
+const Client = require('../')
+const assert = require('assert')
+const async = require('async')
+const ok = require('okay')
 
 describe('async query', function () {
   before(function (done) {
@@ -24,7 +24,7 @@ describe('async query', function () {
   })
 
   it('simple query works', function (done) {
-    var runQuery = function (n, done) {
+    const runQuery = function (n, done) {
       this.client.query('SELECT NOW() AS the_time', function (err, rows) {
         if (err) return done(err)
         assert.equal(rows[0].the_time.getFullYear(), new Date().getFullYear())
@@ -35,14 +35,14 @@ describe('async query', function () {
   })
 
   it('parameters work', function (done) {
-    var runQuery = function (n, done) {
+    const runQuery = function (n, done) {
       this.client.query('SELECT $1::text AS name', ['Brian'], done)
     }.bind(this)
     async.timesSeries(3, runQuery, done)
   })
 
   it('prepared, named statements work', function (done) {
-    var client = this.client
+    const client = this.client
     client.prepare('test', 'SELECT $1::text as name', 1, function (err) {
       if (err) return done(err)
       client.execute(
@@ -80,7 +80,7 @@ describe('async query', function () {
   })
 
   it('returns an error if there was a query error', function (done) {
-    var runErrorQuery = function (n, done) {
+    const runErrorQuery = function (n, done) {
       this.client.query('SELECT ALKJSFDSLFKJ', function (err) {
         assert(err instanceof Error, 'Should return an error instance')
         done()
diff --git a/packages/pg-native/test/query-sync.js b/packages/pg-native/test/query-sync.js
index 7bd86d8c6..baf4e15ec 100644
--- a/packages/pg-native/test/query-sync.js
+++ b/packages/pg-native/test/query-sync.js
@@ -1,5 +1,5 @@
-var Client = require('../')
-var assert = require('assert')
+const Client = require('../')
+const assert = require('assert')
 
 describe('query sync', function () {
   before(function () {
@@ -12,13 +12,13 @@ describe('query sync', function () {
   })
 
   it('simple query works', function () {
-    var rows = this.client.querySync('SELECT NOW() AS the_time')
+    const rows = this.client.querySync('SELECT NOW() AS the_time')
     assert.equal(rows.length, 1)
     assert.equal(rows[0].the_time.getFullYear(), new Date().getFullYear())
   })
 
   it('parameterized query works', function () {
-    var rows = this.client.querySync('SELECT $1::text AS name', ['Brian'])
+    const rows = this.client.querySync('SELECT $1::text AS name', ['Brian'])
     assert.equal(rows.length, 1)
     assert.equal(rows[0].name, 'Brian')
   })
@@ -37,11 +37,11 @@ describe('query sync', function () {
   it('prepared statement works', function () {
     this.client.prepareSync('test', 'SELECT $1::text as name', 1)
 
-    var rows = this.client.executeSync('test', ['Brian'])
+    const rows = this.client.executeSync('test', ['Brian'])
     assert.equal(rows.length, 1)
     assert.equal(rows[0].name, 'Brian')
 
-    var rows2 = this.client.executeSync('test', ['Aaron'])
+    const rows2 = this.client.executeSync('test', ['Aaron'])
     assert.equal(rows2.length, 1)
     assert.equal(rows2[0].name, 'Aaron')
   })
@@ -70,13 +70,13 @@ describe('query sync', function () {
   })
 
   it('is still usable after an error', function () {
-    var rows = this.client.querySync('SELECT NOW()')
+    const rows = this.client.querySync('SELECT NOW()')
     assert(rows, 'should have returned rows')
     assert.equal(rows.length, 1)
   })
 
   it('supports empty query', function () {
-    var rows = this.client.querySync('')
+    const rows = this.client.querySync('')
     assert(rows, 'should return rows')
     assert.equal(rows.length, 0, 'should return no rows')
   })
diff --git a/packages/pg-native/test/version.js b/packages/pg-native/test/version.js
index 204d83682..f8e4d2b29 100644
--- a/packages/pg-native/test/version.js
+++ b/packages/pg-native/test/version.js
@@ -1,6 +1,6 @@
-var Client = require('../')
-var assert = require('assert')
-var semver = require('semver')
+const Client = require('../')
+const assert = require('assert')
+const semver = require('semver')
 
 describe('version', function () {
   it('is exported', function () {
diff --git a/packages/pg-pool/test/connection-timeout.js b/packages/pg-pool/test/connection-timeout.js
index 05e8931df..cb83f7006 100644
--- a/packages/pg-pool/test/connection-timeout.js
+++ b/packages/pg-pool/test/connection-timeout.js
@@ -57,7 +57,7 @@ describe('connection timeout', () => {
       function* () {
         const errors = []
         const pool = new Pool({ connectionTimeoutMillis: 1, port: this.port, host: 'localhost' })
-        for (var i = 0; i < 15; i++) {
+        for (let i = 0; i < 15; i++) {
           try {
             yield pool.connect()
           } catch (e) {
diff --git a/packages/pg-pool/test/error-handling.js b/packages/pg-pool/test/error-handling.js
index 7b1570859..60354325c 100644
--- a/packages/pg-pool/test/error-handling.js
+++ b/packages/pg-pool/test/error-handling.js
@@ -198,7 +198,7 @@ describe('pool error handling', function () {
       co.wrap(function* () {
         const pool = new Pool({ max: 1 })
         const errors = []
-        for (var i = 0; i < 20; i++) {
+        for (let i = 0; i < 20; i++) {
           try {
             yield pool.query('invalid sql')
           } catch (err) {
diff --git a/packages/pg-pool/test/idle-timeout.js b/packages/pg-pool/test/idle-timeout.js
index 0bb097565..c1dee48f6 100644
--- a/packages/pg-pool/test/idle-timeout.js
+++ b/packages/pg-pool/test/idle-timeout.js
@@ -54,8 +54,8 @@ describe('idle timeout', () => {
     co.wrap(function* () {
       const pool = new Pool({ idleTimeoutMillis: 1 })
       const results = []
-      for (var i = 0; i < 20; i++) {
-        let query = pool.query('SELECT NOW()')
+      for (let i = 0; i < 20; i++) {
+        const query = pool.query('SELECT NOW()')
         expect(pool.idleCount).to.equal(0)
         expect(pool.totalCount).to.equal(1)
         results.push(yield query)
@@ -72,8 +72,8 @@ describe('idle timeout', () => {
     co.wrap(function* () {
       const pool = new Pool({ idleTimeoutMillis: 1 })
       const results = []
-      for (var i = 0; i < 20; i++) {
-        let client = yield pool.connect()
+      for (let i = 0; i < 20; i++) {
+        const client = yield pool.connect()
         expect(pool.totalCount).to.equal(1)
         expect(pool.idleCount).to.equal(0)
         yield wait(10)
diff --git a/packages/pg-pool/test/lifetime-timeout.js b/packages/pg-pool/test/lifetime-timeout.js
index 4eac10778..0cdd8c886 100644
--- a/packages/pg-pool/test/lifetime-timeout.js
+++ b/packages/pg-pool/test/lifetime-timeout.js
@@ -32,7 +32,7 @@ describe('lifetime timeout', () => {
     'can remove expired clients and recreate them',
     co.wrap(function* () {
       const pool = new Pool({ maxLifetimeSeconds: 1 })
-      let query = pool.query('SELECT pg_sleep(1.4)')
+      const query = pool.query('SELECT pg_sleep(1.4)')
       expect(pool.expiredCount).to.equal(0)
       expect(pool.totalCount).to.equal(1)
       yield query
diff --git a/packages/pg-protocol/src/b.ts b/packages/pg-protocol/src/b.ts
index 088ca1857..8357623a5 100644
--- a/packages/pg-protocol/src/b.ts
+++ b/packages/pg-protocol/src/b.ts
@@ -4,7 +4,7 @@ import { BufferReader } from './buffer-reader'
 
 const LOOPS = 1000
 let count = 0
-let start = Date.now()
+const start = Date.now()
 
 const reader = new BufferReader()
 const buffer = Buffer.from([33, 33, 33, 33, 33, 33, 33, 0])
diff --git a/packages/pg-protocol/src/buffer-writer.ts b/packages/pg-protocol/src/buffer-writer.ts
index 756cdc9f3..cebb0d9ed 100644
--- a/packages/pg-protocol/src/buffer-writer.ts
+++ b/packages/pg-protocol/src/buffer-writer.ts
@@ -9,12 +9,12 @@ export class Writer {
   }
 
   private ensure(size: number): void {
-    var remaining = this.buffer.length - this.offset
+    const remaining = this.buffer.length - this.offset
     if (remaining < size) {
-      var oldBuffer = this.buffer
+      const oldBuffer = this.buffer
       // exponential growth factor of around ~ 1.5
       // https://stackoverflow.com/questions/2269063/buffer-growth-strategy
-      var newSize = oldBuffer.length + (oldBuffer.length >> 1) + size
+      const newSize = oldBuffer.length + (oldBuffer.length >> 1) + size
       this.buffer = Buffer.allocUnsafe(newSize)
       oldBuffer.copy(this.buffer)
     }
@@ -40,7 +40,7 @@ export class Writer {
     if (!string) {
       this.ensure(1)
     } else {
-      var len = Buffer.byteLength(string)
+      const len = Buffer.byteLength(string)
       this.ensure(len + 1) // +1 for null terminator
       this.buffer.write(string, this.offset, 'utf-8')
       this.offset += len
@@ -51,7 +51,7 @@ export class Writer {
   }
 
   public addString(string: string = ''): Writer {
-    var len = Buffer.byteLength(string)
+    const len = Buffer.byteLength(string)
     this.ensure(len)
     this.buffer.write(string, this.offset)
     this.offset += len
@@ -76,7 +76,7 @@ export class Writer {
   }
 
   public flush(code?: number): Buffer {
-    var result = this.join(code)
+    const result = this.join(code)
     this.offset = 5
     this.headerPosition = 0
     this.buffer = Buffer.allocUnsafe(this.size)
diff --git a/packages/pg-protocol/src/inbound-parser.test.ts b/packages/pg-protocol/src/inbound-parser.test.ts
index adf5aac66..6f576cbfb 100644
--- a/packages/pg-protocol/src/inbound-parser.test.ts
+++ b/packages/pg-protocol/src/inbound-parser.test.ts
@@ -5,16 +5,16 @@ import assert from 'assert'
 import { PassThrough } from 'stream'
 import { BackendMessage } from './messages'
 
-var authOkBuffer = buffers.authenticationOk()
-var paramStatusBuffer = buffers.parameterStatus('client_encoding', 'UTF8')
-var readyForQueryBuffer = buffers.readyForQuery()
-var backendKeyDataBuffer = buffers.backendKeyData(1, 2)
-var commandCompleteBuffer = buffers.commandComplete('SELECT 3')
-var parseCompleteBuffer = buffers.parseComplete()
-var bindCompleteBuffer = buffers.bindComplete()
-var portalSuspendedBuffer = buffers.portalSuspended()
-
-var row1 = {
+const authOkBuffer = buffers.authenticationOk()
+const paramStatusBuffer = buffers.parameterStatus('client_encoding', 'UTF8')
+const readyForQueryBuffer = buffers.readyForQuery()
+const backendKeyDataBuffer = buffers.backendKeyData(1, 2)
+const commandCompleteBuffer = buffers.commandComplete('SELECT 3')
+const parseCompleteBuffer = buffers.parseComplete()
+const bindCompleteBuffer = buffers.bindComplete()
+const portalSuspendedBuffer = buffers.portalSuspended()
+
+const row1 = {
   name: 'id',
   tableID: 1,
   attributeNumber: 2,
@@ -23,10 +23,10 @@ var row1 = {
   typeModifier: 5,
   formatCode: 0,
 }
-var oneRowDescBuff = buffers.rowDescription([row1])
+const oneRowDescBuff = buffers.rowDescription([row1])
 row1.name = 'bang'
 
-var twoRowBuf = buffers.rowDescription([
+const twoRowBuf = buffers.rowDescription([
   row1,
   {
     name: 'whoah',
@@ -39,7 +39,7 @@ var twoRowBuf = buffers.rowDescription([
   },
 ])
 
-var rowWithBigOids = {
+const rowWithBigOids = {
   name: 'bigoid',
   tableID: 3000000001,
   attributeNumber: 2,
@@ -48,60 +48,60 @@ var rowWithBigOids = {
   typeModifier: 5,
   formatCode: 0,
 }
-var bigOidDescBuff = buffers.rowDescription([rowWithBigOids])
+const bigOidDescBuff = buffers.rowDescription([rowWithBigOids])
 
-var emptyRowFieldBuf = new BufferList().addInt16(0).join(true, 'D')
+let emptyRowFieldBuf = new BufferList().addInt16(0).join(true, 'D')
 
-var emptyRowFieldBuf = buffers.dataRow([])
+emptyRowFieldBuf = buffers.dataRow([])
 
-var oneFieldBuf = new BufferList()
+let oneFieldBuf = new BufferList()
   .addInt16(1) // number of fields
   .addInt32(5) // length of bytes of fields
   .addCString('test')
   .join(true, 'D')
 
-var oneFieldBuf = buffers.dataRow(['test'])
+oneFieldBuf = buffers.dataRow(['test'])
 
-var expectedAuthenticationOkayMessage = {
+const expectedAuthenticationOkayMessage = {
   name: 'authenticationOk',
   length: 8,
 }
 
-var expectedParameterStatusMessage = {
+const expectedParameterStatusMessage = {
   name: 'parameterStatus',
   parameterName: 'client_encoding',
   parameterValue: 'UTF8',
   length: 25,
 }
 
-var expectedBackendKeyDataMessage = {
+const expectedBackendKeyDataMessage = {
   name: 'backendKeyData',
   processID: 1,
   secretKey: 2,
 }
 
-var expectedReadyForQueryMessage = {
+const expectedReadyForQueryMessage = {
   name: 'readyForQuery',
   length: 5,
   status: 'I',
 }
 
-var expectedCommandCompleteMessage = {
+const expectedCommandCompleteMessage = {
   name: 'commandComplete',
   length: 13,
   text: 'SELECT 3',
 }
-var emptyRowDescriptionBuffer = new BufferList()
+const emptyRowDescriptionBuffer = new BufferList()
   .addInt16(0) // number of fields
   .join(true, 'T')
 
-var expectedEmptyRowDescriptionMessage = {
+const expectedEmptyRowDescriptionMessage = {
   name: 'rowDescription',
   length: 6,
   fieldCount: 0,
   fields: [],
 }
-var expectedOneRowMessage = {
+const expectedOneRowMessage = {
   name: 'rowDescription',
   length: 27,
   fieldCount: 1,
@@ -118,7 +118,7 @@ var expectedOneRowMessage = {
   ],
 }
 
-var expectedTwoRowMessage = {
+const expectedTwoRowMessage = {
   name: 'rowDescription',
   length: 53,
   fieldCount: 2,
@@ -143,7 +143,7 @@ var expectedTwoRowMessage = {
     },
   ],
 }
-var expectedBigOidMessage = {
+const expectedBigOidMessage = {
   name: 'rowDescription',
   length: 31,
   fieldCount: 1,
@@ -160,36 +160,36 @@ var expectedBigOidMessage = {
   ],
 }
 
-var emptyParameterDescriptionBuffer = new BufferList()
+const emptyParameterDescriptionBuffer = new BufferList()
   .addInt16(0) // number of parameters
   .join(true, 't')
 
-var oneParameterDescBuf = buffers.parameterDescription([1111])
+const oneParameterDescBuf = buffers.parameterDescription([1111])
 
-var twoParameterDescBuf = buffers.parameterDescription([2222, 3333])
+const twoParameterDescBuf = buffers.parameterDescription([2222, 3333])
 
-var expectedEmptyParameterDescriptionMessage = {
+const expectedEmptyParameterDescriptionMessage = {
   name: 'parameterDescription',
   length: 6,
   parameterCount: 0,
   dataTypeIDs: [],
 }
 
-var expectedOneParameterMessage = {
+const expectedOneParameterMessage = {
   name: 'parameterDescription',
   length: 10,
   parameterCount: 1,
   dataTypeIDs: [1111],
 }
 
-var expectedTwoParameterMessage = {
+const expectedTwoParameterMessage = {
   name: 'parameterDescription',
   length: 14,
   parameterCount: 2,
   dataTypeIDs: [2222, 3333],
 }
 
-var testForMessage = function (buffer: Buffer, expectedMessage: any) {
+const testForMessage = function (buffer: Buffer, expectedMessage: any) {
   it('recieves and parses ' + expectedMessage.name, async () => {
     const messages = await parseBuffers([buffer])
     const [lastMessage] = messages
@@ -200,38 +200,38 @@ var testForMessage = function (buffer: Buffer, expectedMessage: any) {
   })
 }
 
-var plainPasswordBuffer = buffers.authenticationCleartextPassword()
-var md5PasswordBuffer = buffers.authenticationMD5Password()
-var SASLBuffer = buffers.authenticationSASL()
-var SASLContinueBuffer = buffers.authenticationSASLContinue()
-var SASLFinalBuffer = buffers.authenticationSASLFinal()
+const plainPasswordBuffer = buffers.authenticationCleartextPassword()
+const md5PasswordBuffer = buffers.authenticationMD5Password()
+const SASLBuffer = buffers.authenticationSASL()
+const SASLContinueBuffer = buffers.authenticationSASLContinue()
+const SASLFinalBuffer = buffers.authenticationSASLFinal()
 
-var expectedPlainPasswordMessage = {
+const expectedPlainPasswordMessage = {
   name: 'authenticationCleartextPassword',
 }
 
-var expectedMD5PasswordMessage = {
+const expectedMD5PasswordMessage = {
   name: 'authenticationMD5Password',
   salt: Buffer.from([1, 2, 3, 4]),
 }
 
-var expectedSASLMessage = {
+const expectedSASLMessage = {
   name: 'authenticationSASL',
   mechanisms: ['SCRAM-SHA-256'],
 }
 
-var expectedSASLContinueMessage = {
+const expectedSASLContinueMessage = {
   name: 'authenticationSASLContinue',
   data: 'data',
 }
 
-var expectedSASLFinalMessage = {
+const expectedSASLFinalMessage = {
   name: 'authenticationSASLFinal',
   data: 'data',
 }
 
-var notificationResponseBuffer = buffers.notification(4, 'hi', 'boom')
-var expectedNotificationResponseMessage = {
+const notificationResponseBuffer = buffers.notification(4, 'hi', 'boom')
+const expectedNotificationResponseMessage = {
   name: 'notification',
   processId: 4,
   channel: 'hi',
@@ -316,7 +316,7 @@ describe('PgPacketStream', function () {
 
   describe('notice message', function () {
     // this uses the same logic as error message
-    var buff = buffers.notice([{ type: 'C', value: 'code' }])
+    const buff = buffers.notice([{ type: 'C', value: 'code' }])
     testForMessage(buff, {
       name: 'notice',
       code: 'code',
@@ -328,7 +328,7 @@ describe('PgPacketStream', function () {
   })
 
   describe('with all the fields', function () {
-    var buffer = buffers.error([
+    const buffer = buffers.error([
       {
         type: 'S',
         value: 'ERROR',
@@ -474,7 +474,7 @@ describe('PgPacketStream', function () {
   // tcp packets anywhere, we need to make sure we can parse every single
   // split on a tcp message
   describe('split buffer, single message parsing', function () {
-    var fullBuffer = buffers.dataRow([null, 'bang', 'zug zug', null, '!'])
+    const fullBuffer = buffers.dataRow([null, 'bang', 'zug zug', null, '!'])
 
     it('parses when full buffer comes in', async function () {
       const messages = await parseBuffers([fullBuffer])
@@ -487,9 +487,9 @@ describe('PgPacketStream', function () {
       assert.equal(message.fields[4], '!')
     })
 
-    var testMessageRecievedAfterSpiltAt = async function (split: number) {
-      var firstBuffer = Buffer.alloc(fullBuffer.length - split)
-      var secondBuffer = Buffer.alloc(fullBuffer.length - firstBuffer.length)
+    const testMessageRecievedAfterSpiltAt = async function (split: number) {
+      const firstBuffer = Buffer.alloc(fullBuffer.length - split)
+      const secondBuffer = Buffer.alloc(fullBuffer.length - firstBuffer.length)
       fullBuffer.copy(firstBuffer, 0, 0)
       fullBuffer.copy(secondBuffer, 0, firstBuffer.length)
       const messages = await parseBuffers([fullBuffer])
@@ -518,13 +518,13 @@ describe('PgPacketStream', function () {
   })
 
   describe('split buffer, multiple message parsing', function () {
-    var dataRowBuffer = buffers.dataRow(['!'])
-    var readyForQueryBuffer = buffers.readyForQuery()
-    var fullBuffer = Buffer.alloc(dataRowBuffer.length + readyForQueryBuffer.length)
+    const dataRowBuffer = buffers.dataRow(['!'])
+    const readyForQueryBuffer = buffers.readyForQuery()
+    const fullBuffer = Buffer.alloc(dataRowBuffer.length + readyForQueryBuffer.length)
     dataRowBuffer.copy(fullBuffer, 0, 0)
     readyForQueryBuffer.copy(fullBuffer, dataRowBuffer.length, 0)
 
-    var verifyMessages = function (messages: any[]) {
+    const verifyMessages = function (messages: any[]) {
       assert.strictEqual(messages.length, 2)
       assert.deepEqual(messages[0], {
         name: 'dataRow',
@@ -545,9 +545,9 @@ describe('PgPacketStream', function () {
       verifyMessages(messages)
     })
 
-    var splitAndVerifyTwoMessages = async function (split: number) {
-      var firstBuffer = Buffer.alloc(fullBuffer.length - split)
-      var secondBuffer = Buffer.alloc(fullBuffer.length - firstBuffer.length)
+    const splitAndVerifyTwoMessages = async function (split: number) {
+      const firstBuffer = Buffer.alloc(fullBuffer.length - split)
+      const secondBuffer = Buffer.alloc(fullBuffer.length - firstBuffer.length)
       fullBuffer.copy(firstBuffer, 0, 0)
       fullBuffer.copy(secondBuffer, 0, firstBuffer.length)
       const messages = await parseBuffers([firstBuffer, secondBuffer])
diff --git a/packages/pg-protocol/src/outbound-serializer.test.ts b/packages/pg-protocol/src/outbound-serializer.test.ts
index f6669becd..48dc25b20 100644
--- a/packages/pg-protocol/src/outbound-serializer.test.ts
+++ b/packages/pg-protocol/src/outbound-serializer.test.ts
@@ -46,7 +46,7 @@ describe('serializer', () => {
   })
 
   it('builds query message', function () {
-    var txt = 'select * from boom'
+    const txt = 'select * from boom'
     const actual = serialize.query(txt)
     assert.deepEqual(actual, new BufferList().addCString(txt).join(true, 'Q'))
   })
@@ -54,7 +54,7 @@ describe('serializer', () => {
   describe('parse message', () => {
     it('builds parse message', function () {
       const actual = serialize.parse({ text: '!' })
-      var expected = new BufferList().addCString('').addCString('!').addInt16(0).join(true, 'P')
+      const expected = new BufferList().addCString('').addCString('!').addInt16(0).join(true, 'P')
       assert.deepEqual(actual, expected)
     })
 
@@ -64,7 +64,7 @@ describe('serializer', () => {
         text: 'select * from boom',
         types: [],
       })
-      var expected = new BufferList().addCString('boom').addCString('select * from boom').addInt16(0).join(true, 'P')
+      const expected = new BufferList().addCString('boom').addCString('select * from boom').addInt16(0).join(true, 'P')
       assert.deepEqual(actual, expected)
     })
 
@@ -74,7 +74,7 @@ describe('serializer', () => {
         text: 'select * from bang where name = $1',
         types: [1, 2, 3, 4],
       })
-      var expected = new BufferList()
+      const expected = new BufferList()
         .addCString('force')
         .addCString('select * from bang where name = $1')
         .addInt16(4)
@@ -91,7 +91,7 @@ describe('serializer', () => {
     it('with no values', function () {
       const actual = serialize.bind()
 
-      var expectedBuffer = new BufferList()
+      const expectedBuffer = new BufferList()
         .addCString('')
         .addCString('')
         .addInt16(0)
@@ -107,7 +107,7 @@ describe('serializer', () => {
         statement: 'woo',
         values: ['1', 'hi', null, 'zing'],
       })
-      var expectedBuffer = new BufferList()
+      const expectedBuffer = new BufferList()
         .addCString('bang') // portal name
         .addCString('woo') // statement name
         .addInt16(4)
@@ -136,7 +136,7 @@ describe('serializer', () => {
       values: ['1', 'hi', null, 'zing'],
       valueMapper: () => null,
     })
-    var expectedBuffer = new BufferList()
+    const expectedBuffer = new BufferList()
       .addCString('bang') // portal name
       .addCString('woo') // statement name
       .addInt16(4)
@@ -160,7 +160,7 @@ describe('serializer', () => {
       statement: 'woo',
       values: ['1', 'hi', null, Buffer.from('zing', 'utf8')],
     })
-    var expectedBuffer = new BufferList()
+    const expectedBuffer = new BufferList()
       .addCString('bang') // portal name
       .addCString('woo') // statement name
       .addInt16(4) // value count
@@ -184,7 +184,7 @@ describe('serializer', () => {
   describe('builds execute message', function () {
     it('for unamed portal with no row limit', function () {
       const actual = serialize.execute()
-      var expectedBuffer = new BufferList().addCString('').addInt32(0).join(true, 'E')
+      const expectedBuffer = new BufferList().addCString('').addInt32(0).join(true, 'E')
       assert.deepEqual(actual, expectedBuffer)
     })
 
@@ -193,39 +193,39 @@ describe('serializer', () => {
         portal: 'my favorite portal',
         rows: 100,
       })
-      var expectedBuffer = new BufferList().addCString('my favorite portal').addInt32(100).join(true, 'E')
+      const expectedBuffer = new BufferList().addCString('my favorite portal').addInt32(100).join(true, 'E')
       assert.deepEqual(actual, expectedBuffer)
     })
   })
 
   it('builds flush command', function () {
     const actual = serialize.flush()
-    var expected = new BufferList().join(true, 'H')
+    const expected = new BufferList().join(true, 'H')
     assert.deepEqual(actual, expected)
   })
 
   it('builds sync command', function () {
     const actual = serialize.sync()
-    var expected = new BufferList().join(true, 'S')
+    const expected = new BufferList().join(true, 'S')
     assert.deepEqual(actual, expected)
   })
 
   it('builds end command', function () {
     const actual = serialize.end()
-    var expected = Buffer.from([0x58, 0, 0, 0, 4])
+    const expected = Buffer.from([0x58, 0, 0, 0, 4])
     assert.deepEqual(actual, expected)
   })
 
   describe('builds describe command', function () {
     it('describe statement', function () {
       const actual = serialize.describe({ type: 'S', name: 'bang' })
-      var expected = new BufferList().addChar('S').addCString('bang').join(true, 'D')
+      const expected = new BufferList().addChar('S').addCString('bang').join(true, 'D')
       assert.deepEqual(actual, expected)
     })
 
     it('describe unnamed portal', function () {
       const actual = serialize.describe({ type: 'P' })
-      var expected = new BufferList().addChar('P').addCString('').join(true, 'D')
+      const expected = new BufferList().addChar('P').addCString('').join(true, 'D')
       assert.deepEqual(actual, expected)
     })
   })
@@ -233,13 +233,13 @@ describe('serializer', () => {
   describe('builds close command', function () {
     it('describe statement', function () {
       const actual = serialize.close({ type: 'S', name: 'bang' })
-      var expected = new BufferList().addChar('S').addCString('bang').join(true, 'C')
+      const expected = new BufferList().addChar('S').addCString('bang').join(true, 'C')
       assert.deepEqual(actual, expected)
     })
 
     it('describe unnamed portal', function () {
       const actual = serialize.close({ type: 'P' })
-      var expected = new BufferList().addChar('P').addCString('').join(true, 'C')
+      const expected = new BufferList().addChar('P').addCString('').join(true, 'C')
       assert.deepEqual(actual, expected)
     })
   })
diff --git a/packages/pg-protocol/src/serializer.ts b/packages/pg-protocol/src/serializer.ts
index 07e2fe498..fb1dd89db 100644
--- a/packages/pg-protocol/src/serializer.ts
+++ b/packages/pg-protocol/src/serializer.ts
@@ -27,10 +27,10 @@ const startup = (opts: Record<string, string>): Buffer => {
 
   writer.addCString('client_encoding').addCString('UTF8')
 
-  var bodyBuffer = writer.addCString('').flush()
+  const bodyBuffer = writer.addCString('').flush()
   // this message is sent without a code
 
-  var length = bodyBuffer.length + 4
+  const length = bodyBuffer.length + 4
 
   return new Writer().addInt32(length).add(bodyBuffer).flush()
 }
@@ -87,14 +87,14 @@ const parse = (query: ParseOpts): Buffer => {
 
   const types = query.types || emptyArray
 
-  var len = types.length
+  const len = types.length
 
-  var buffer = writer
+  const buffer = writer
     .addCString(name) // name of query
     .addCString(query.text) // actual query text
     .addInt16(len)
 
-  for (var i = 0; i < len; i++) {
+  for (let i = 0; i < len; i++) {
     buffer.addInt32(types[i])
   }
 
diff --git a/packages/pg-protocol/src/testing/buffer-list.ts b/packages/pg-protocol/src/testing/buffer-list.ts
index 15ac785cc..4888b8577 100644
--- a/packages/pg-protocol/src/testing/buffer-list.ts
+++ b/packages/pg-protocol/src/testing/buffer-list.ts
@@ -24,16 +24,16 @@ export default class BufferList {
   }
 
   public addCString(val: string, front?: boolean) {
-    var len = Buffer.byteLength(val)
-    var buffer = Buffer.alloc(len + 1)
+    const len = Buffer.byteLength(val)
+    const buffer = Buffer.alloc(len + 1)
     buffer.write(val)
     buffer[len] = 0
     return this.add(buffer, front)
   }
 
   public addString(val: string, front?: boolean) {
-    var len = Buffer.byteLength(val)
-    var buffer = Buffer.alloc(len)
+    const len = Buffer.byteLength(val)
+    const buffer = Buffer.alloc(len)
     buffer.write(val)
     return this.add(buffer, front)
   }
@@ -47,7 +47,7 @@ export default class BufferList {
   }
 
   public join(appendLength?: boolean, char?: string): Buffer {
-    var length = this.getByteLength()
+    let length = this.getByteLength()
     if (appendLength) {
       this.addInt32(length + 4, true)
       return this.join(false, char)
@@ -56,8 +56,8 @@ export default class BufferList {
       this.addChar(char, true)
       length++
     }
-    var result = Buffer.alloc(length)
-    var index = 0
+    const result = Buffer.alloc(length)
+    let index = 0
     this.buffers.forEach(function (buffer) {
       buffer.copy(result, index, 0)
       index += buffer.length
@@ -66,8 +66,8 @@ export default class BufferList {
   }
 
   public static concat(): Buffer {
-    var total = new BufferList()
-    for (var i = 0; i < arguments.length; i++) {
+    const total = new BufferList()
+    for (let i = 0; i < arguments.length; i++) {
       total.add(arguments[i])
     }
     return total.join()
diff --git a/packages/pg-protocol/src/testing/test-buffers.ts b/packages/pg-protocol/src/testing/test-buffers.ts
index a4d49f322..1f0d71f2d 100644
--- a/packages/pg-protocol/src/testing/test-buffers.ts
+++ b/packages/pg-protocol/src/testing/test-buffers.ts
@@ -47,7 +47,7 @@ const buffers = {
 
   rowDescription: function (fields: any[]) {
     fields = fields || []
-    var buf = new BufferList()
+    const buf = new BufferList()
     buf.addInt16(fields.length)
     fields.forEach(function (field) {
       buf
@@ -64,7 +64,7 @@ const buffers = {
 
   parameterDescription: function (dataTypeIDs: number[]) {
     dataTypeIDs = dataTypeIDs || []
-    var buf = new BufferList()
+    const buf = new BufferList()
     buf.addInt16(dataTypeIDs.length)
     dataTypeIDs.forEach(function (dataTypeID) {
       buf.addInt32(dataTypeID)
@@ -74,13 +74,13 @@ const buffers = {
 
   dataRow: function (columns: any[]) {
     columns = columns || []
-    var buf = new BufferList()
+    const buf = new BufferList()
     buf.addInt16(columns.length)
     columns.forEach(function (col) {
       if (col == null) {
         buf.addInt32(-1)
       } else {
-        var strBuf = Buffer.from(col, 'utf8')
+        const strBuf = Buffer.from(col, 'utf8')
         buf.addInt32(strBuf.length)
         buf.add(strBuf)
       }
@@ -98,7 +98,7 @@ const buffers = {
 
   errorOrNotice: function (fields: any) {
     fields = fields || []
-    var buf = new BufferList()
+    const buf = new BufferList()
     fields.forEach(function (field: any) {
       buf.addChar(field.type)
       buf.addCString(field.value)
diff --git a/packages/pg/bench.js b/packages/pg/bench.js
index 223b10278..32b370a4c 100644
--- a/packages/pg/bench.js
+++ b/packages/pg/bench.js
@@ -23,7 +23,7 @@ const exec = async (client, q) => {
 }
 
 const bench = async (client, q, time) => {
-  let start = Date.now()
+  const start = Date.now()
   let count = 0
   while (true) {
     await exec(client, q)
diff --git a/packages/pg/lib/client.js b/packages/pg/lib/client.js
index 527f62e4f..c26137841 100644
--- a/packages/pg/lib/client.js
+++ b/packages/pg/lib/client.js
@@ -1,14 +1,14 @@
 'use strict'
 
-var EventEmitter = require('events').EventEmitter
-var utils = require('./utils')
-var sasl = require('./crypto/sasl')
-var TypeOverrides = require('./type-overrides')
-
-var ConnectionParameters = require('./connection-parameters')
-var Query = require('./query')
-var defaults = require('./defaults')
-var Connection = require('./connection')
+const EventEmitter = require('events').EventEmitter
+const utils = require('./utils')
+const sasl = require('./crypto/sasl')
+const TypeOverrides = require('./type-overrides')
+
+const ConnectionParameters = require('./connection-parameters')
+const Query = require('./query')
+const defaults = require('./defaults')
+const Connection = require('./connection')
 const crypto = require('./crypto/utils')
 
 class Client extends EventEmitter {
@@ -32,7 +32,7 @@ class Client extends EventEmitter {
 
     this.replication = this.connectionParameters.replication
 
-    var c = config || {}
+    const c = config || {}
 
     this._Promise = c.Promise || global.Promise
     this._types = new TypeOverrides(c.types)
@@ -86,8 +86,8 @@ class Client extends EventEmitter {
   }
 
   _connect(callback) {
-    var self = this
-    var con = this.connection
+    const self = this
+    const con = this.connection
     this._connectionCallback = callback
 
     if (this._connecting || this._connected) {
@@ -417,14 +417,14 @@ class Client extends EventEmitter {
   }
 
   getStartupConf() {
-    var params = this.connectionParameters
+    const params = this.connectionParameters
 
-    var data = {
+    const data = {
       user: params.user,
       database: params.database,
     }
 
-    var appName = params.application_name || params.fallback_application_name
+    const appName = params.application_name || params.fallback_application_name
     if (appName) {
       data.application_name = appName
     }
@@ -449,7 +449,7 @@ class Client extends EventEmitter {
 
   cancel(client, query) {
     if (client.activeQuery === query) {
-      var con = this.connection
+      const con = this.connection
 
       if (this.host && this.host.indexOf('/') === 0) {
         con.connect(this.host + '/.s.PGSQL.' + this.port)
@@ -509,11 +509,11 @@ class Client extends EventEmitter {
 
   query(config, values, callback) {
     // can take in strings, config object or query object
-    var query
-    var result
-    var readTimeout
-    var readTimeoutTimer
-    var queryCallback
+    let query
+    let result
+    let readTimeout
+    let readTimeoutTimer
+    let queryCallback
 
     if (config === null || config === undefined) {
       throw new TypeError('Client was passed a null or undefined query')
@@ -542,7 +542,7 @@ class Client extends EventEmitter {
       queryCallback = query.callback
 
       readTimeoutTimer = setTimeout(() => {
-        var error = new Error('Query read timeout')
+        const error = new Error('Query read timeout')
 
         process.nextTick(() => {
           query.handleError(error, this.connection)
@@ -555,7 +555,7 @@ class Client extends EventEmitter {
         query.callback = () => {}
 
         // Remove from queue
-        var index = this.queryQueue.indexOf(query)
+        const index = this.queryQueue.indexOf(query)
         if (index > -1) {
           this.queryQueue.splice(index, 1)
         }
diff --git a/packages/pg/lib/connection-parameters.js b/packages/pg/lib/connection-parameters.js
index 6a535a820..a7b941c10 100644
--- a/packages/pg/lib/connection-parameters.js
+++ b/packages/pg/lib/connection-parameters.js
@@ -1,12 +1,12 @@
 'use strict'
 
-var dns = require('dns')
+const dns = require('dns')
 
-var defaults = require('./defaults')
+const defaults = require('./defaults')
 
-var parse = require('pg-connection-string').parse // parses a connection string
+const parse = require('pg-connection-string').parse // parses a connection string
 
-var val = function (key, config, envVar) {
+const val = function (key, config, envVar) {
   if (envVar === undefined) {
     envVar = process.env['PG' + key.toUpperCase()]
   } else if (envVar === false) {
@@ -18,7 +18,7 @@ var val = function (key, config, envVar) {
   return config[key] || envVar || defaults[key]
 }
 
-var readSSLConfigFromEnvironment = function () {
+const readSSLConfigFromEnvironment = function () {
   switch (process.env.PGSSLMODE) {
     case 'disable':
       return false
@@ -34,12 +34,12 @@ var readSSLConfigFromEnvironment = function () {
 }
 
 // Convert arg to a string, surround in single quotes, and escape single quotes and backslashes
-var quoteParamValue = function (value) {
+const quoteParamValue = function (value) {
   return "'" + ('' + value).replace(/\\/g, '\\\\').replace(/'/g, "\\'") + "'"
 }
 
-var add = function (params, config, paramName) {
-  var value = config[paramName]
+const add = function (params, config, paramName) {
+  const value = config[paramName]
   if (value !== undefined && value !== null) {
     params.push(paramName + '=' + quoteParamValue(value))
   }
@@ -125,7 +125,7 @@ class ConnectionParameters {
   }
 
   getLibpqConnectionString(cb) {
-    var params = []
+    const params = []
     add(params, this, 'user')
     add(params, this, 'password')
     add(params, this, 'port')
@@ -134,7 +134,7 @@ class ConnectionParameters {
     add(params, this, 'connect_timeout')
     add(params, this, 'options')
 
-    var ssl = typeof this.ssl === 'object' ? this.ssl : this.ssl ? { sslmode: this.ssl } : {}
+    const ssl = typeof this.ssl === 'object' ? this.ssl : this.ssl ? { sslmode: this.ssl } : {}
     add(params, ssl, 'sslmode')
     add(params, ssl, 'sslca')
     add(params, ssl, 'sslkey')
diff --git a/packages/pg/lib/connection.js b/packages/pg/lib/connection.js
index c426b152c..8045af858 100644
--- a/packages/pg/lib/connection.js
+++ b/packages/pg/lib/connection.js
@@ -1,6 +1,6 @@
 'use strict'
 
-var EventEmitter = require('events').EventEmitter
+const EventEmitter = require('events').EventEmitter
 
 const { parse, serialize } = require('pg-protocol')
 const { getStream, getSecureStream } = require('./stream')
@@ -27,7 +27,7 @@ class Connection extends EventEmitter {
     this.ssl = config.ssl || false
     this._ending = false
     this._emitMessage = false
-    var self = this
+    const self = this
     this.on('newListener', function (eventName) {
       if (eventName === 'message') {
         self._emitMessage = true
@@ -36,7 +36,7 @@ class Connection extends EventEmitter {
   }
 
   connect(port, host) {
-    var self = this
+    const self = this
 
     this._connecting = true
     this.stream.setNoDelay(true)
@@ -67,7 +67,7 @@ class Connection extends EventEmitter {
     }
 
     this.stream.once('data', function (buffer) {
-      var responseCode = buffer.toString('utf8')
+      const responseCode = buffer.toString('utf8')
       switch (responseCode) {
         case 'S': // Server supports SSL connections, continue with a secure connection
           break
@@ -91,7 +91,7 @@ class Connection extends EventEmitter {
         }
       }
 
-      var net = require('net')
+      const net = require('net')
       if (net.isIP && net.isIP(host) === 0) {
         options.servername = host
       }
@@ -109,7 +109,7 @@ class Connection extends EventEmitter {
 
   attachListeners(stream) {
     parse(stream, (msg) => {
-      var eventName = msg.name === 'error' ? 'errorMessage' : msg.name
+      const eventName = msg.name === 'error' ? 'errorMessage' : msg.name
       if (this._emitMessage) {
         this.emit('message', msg)
       }
diff --git a/packages/pg/lib/crypto/sasl.js b/packages/pg/lib/crypto/sasl.js
index 04ae19724..b7304265e 100644
--- a/packages/pg/lib/crypto/sasl.js
+++ b/packages/pg/lib/crypto/sasl.js
@@ -38,19 +38,19 @@ async function continueSession(session, password, serverData) {
     throw new Error('SASL: SCRAM-SERVER-FIRST-MESSAGE: server nonce is too short')
   }
 
-  var clientFirstMessageBare = 'n=*,r=' + session.clientNonce
-  var serverFirstMessage = 'r=' + sv.nonce + ',s=' + sv.salt + ',i=' + sv.iteration
-  var clientFinalMessageWithoutProof = 'c=biws,r=' + sv.nonce
-  var authMessage = clientFirstMessageBare + ',' + serverFirstMessage + ',' + clientFinalMessageWithoutProof
-
-  var saltBytes = Buffer.from(sv.salt, 'base64')
-  var saltedPassword = await crypto.deriveKey(password, saltBytes, sv.iteration)
-  var clientKey = await crypto.hmacSha256(saltedPassword, 'Client Key')
-  var storedKey = await crypto.sha256(clientKey)
-  var clientSignature = await crypto.hmacSha256(storedKey, authMessage)
-  var clientProof = xorBuffers(Buffer.from(clientKey), Buffer.from(clientSignature)).toString('base64')
-  var serverKey = await crypto.hmacSha256(saltedPassword, 'Server Key')
-  var serverSignatureBytes = await crypto.hmacSha256(serverKey, authMessage)
+  const clientFirstMessageBare = 'n=*,r=' + session.clientNonce
+  const serverFirstMessage = 'r=' + sv.nonce + ',s=' + sv.salt + ',i=' + sv.iteration
+  const clientFinalMessageWithoutProof = 'c=biws,r=' + sv.nonce
+  const authMessage = clientFirstMessageBare + ',' + serverFirstMessage + ',' + clientFinalMessageWithoutProof
+
+  const saltBytes = Buffer.from(sv.salt, 'base64')
+  const saltedPassword = await crypto.deriveKey(password, saltBytes, sv.iteration)
+  const clientKey = await crypto.hmacSha256(saltedPassword, 'Client Key')
+  const storedKey = await crypto.sha256(clientKey)
+  const clientSignature = await crypto.hmacSha256(storedKey, authMessage)
+  const clientProof = xorBuffers(Buffer.from(clientKey), Buffer.from(clientSignature)).toString('base64')
+  const serverKey = await crypto.hmacSha256(saltedPassword, 'Server Key')
+  const serverSignatureBytes = await crypto.hmacSha256(serverKey, authMessage)
 
   session.message = 'SASLResponse'
   session.serverSignature = Buffer.from(serverSignatureBytes).toString('base64')
diff --git a/packages/pg/lib/crypto/utils-legacy.js b/packages/pg/lib/crypto/utils-legacy.js
index 86544ad00..ac9654319 100644
--- a/packages/pg/lib/crypto/utils-legacy.js
+++ b/packages/pg/lib/crypto/utils-legacy.js
@@ -10,8 +10,8 @@ function md5(string) {
 
 // See AuthenticationMD5Password at https://www.postgresql.org/docs/current/static/protocol-flow.html
 function postgresMd5PasswordHash(user, password, salt) {
-  var inner = md5(password + user)
-  var outer = md5(Buffer.concat([Buffer.from(inner), salt]))
+  const inner = md5(password + user)
+  const outer = md5(Buffer.concat([Buffer.from(inner), salt]))
   return 'md5' + outer
 }
 
diff --git a/packages/pg/lib/crypto/utils-webcrypto.js b/packages/pg/lib/crypto/utils-webcrypto.js
index 0433f010c..fbfe3b35d 100644
--- a/packages/pg/lib/crypto/utils-webcrypto.js
+++ b/packages/pg/lib/crypto/utils-webcrypto.js
@@ -47,8 +47,8 @@ async function md5(string) {
 
 // See AuthenticationMD5Password at https://www.postgresql.org/docs/current/static/protocol-flow.html
 async function postgresMd5PasswordHash(user, password, salt) {
-  var inner = await md5(password + user)
-  var outer = await md5(Buffer.concat([Buffer.from(inner), salt]))
+  const inner = await md5(password + user)
+  const outer = await md5(Buffer.concat([Buffer.from(inner), salt]))
   return 'md5' + outer
 }
 
diff --git a/packages/pg/lib/defaults.js b/packages/pg/lib/defaults.js
index 5c5d997d2..015909dcd 100644
--- a/packages/pg/lib/defaults.js
+++ b/packages/pg/lib/defaults.js
@@ -72,10 +72,10 @@ module.exports = {
   keepalives_idle: 0,
 }
 
-var pgTypes = require('pg-types')
+const pgTypes = require('pg-types')
 // save default parsers
-var parseBigInteger = pgTypes.getTypeParser(20, 'text')
-var parseBigIntegerArray = pgTypes.getTypeParser(1016, 'text')
+const parseBigInteger = pgTypes.getTypeParser(20, 'text')
+const parseBigIntegerArray = pgTypes.getTypeParser(1016, 'text')
 
 // parse int8 so you can get your count values as actual numbers
 module.exports.__defineSetter__('parseInt8', function (val) {
diff --git a/packages/pg/lib/index.js b/packages/pg/lib/index.js
index 1742d168a..d7b694c2a 100644
--- a/packages/pg/lib/index.js
+++ b/packages/pg/lib/index.js
@@ -1,9 +1,9 @@
 'use strict'
 
-var Client = require('./client')
-var defaults = require('./defaults')
-var Connection = require('./connection')
-var Pool = require('pg-pool')
+const Client = require('./client')
+const defaults = require('./defaults')
+const Connection = require('./connection')
+const Pool = require('pg-pool')
 const { DatabaseError } = require('pg-protocol')
 const { escapeIdentifier, escapeLiteral } = require('./utils')
 
@@ -15,7 +15,7 @@ const poolFactory = (Client) => {
   }
 }
 
-var PG = function (clientConstructor) {
+const PG = function (clientConstructor) {
   this.defaults = defaults
   this.Client = clientConstructor
   this.Query = this.Client.Query
@@ -38,7 +38,7 @@ if (typeof process.env.NODE_PG_FORCE_NATIVE !== 'undefined') {
     configurable: true,
     enumerable: false,
     get() {
-      var native = null
+      let native = null
       try {
         native = new PG(require('./native'))
       } catch (err) {
diff --git a/packages/pg/lib/native/client.js b/packages/pg/lib/native/client.js
index 6494375f1..677011d44 100644
--- a/packages/pg/lib/native/client.js
+++ b/packages/pg/lib/native/client.js
@@ -8,14 +8,14 @@ try {
 } catch (e) {
   throw e
 }
-var TypeOverrides = require('../type-overrides')
-var EventEmitter = require('events').EventEmitter
-var util = require('util')
-var ConnectionParameters = require('../connection-parameters')
+const TypeOverrides = require('../type-overrides')
+const EventEmitter = require('events').EventEmitter
+const util = require('util')
+const ConnectionParameters = require('../connection-parameters')
 
-var NativeQuery = require('./query')
+const NativeQuery = require('./query')
 
-var Client = (module.exports = function (config) {
+const Client = (module.exports = function (config) {
   EventEmitter.call(this)
   config = config || {}
 
@@ -34,7 +34,7 @@ var Client = (module.exports = function (config) {
 
   // keep these on the object for legacy reasons
   // for the time being. TODO: deprecate all this jazz
-  var cp = (this.connectionParameters = new ConnectionParameters(config))
+  const cp = (this.connectionParameters = new ConnectionParameters(config))
   if (config.nativeConnectionString) cp.nativeConnectionString = config.nativeConnectionString
   this.user = cp.user
 
@@ -79,7 +79,7 @@ Client.prototype._errorAllQueries = function (err) {
 // pass an optional callback to be called once connected
 // or with an error if there was a connection error
 Client.prototype._connect = function (cb) {
-  var self = this
+  const self = this
 
   if (this._connecting) {
     process.nextTick(() => cb(new Error('Client has already been connected. You cannot reuse a client.')))
@@ -151,11 +151,11 @@ Client.prototype.connect = function (callback) {
 //    optional string rowMode = 'array' for an array of results
 //  }
 Client.prototype.query = function (config, values, callback) {
-  var query
-  var result
-  var readTimeout
-  var readTimeoutTimer
-  var queryCallback
+  let query
+  let result
+  let readTimeout
+  let readTimeoutTimer
+  let queryCallback
 
   if (config === null || config === undefined) {
     throw new TypeError('Client was passed a null or undefined query')
@@ -186,7 +186,7 @@ Client.prototype.query = function (config, values, callback) {
     queryCallback = query.callback
 
     readTimeoutTimer = setTimeout(() => {
-      var error = new Error('Query read timeout')
+      const error = new Error('Query read timeout')
 
       process.nextTick(() => {
         query.handleError(error, this.connection)
@@ -199,7 +199,7 @@ Client.prototype.query = function (config, values, callback) {
       query.callback = () => {}
 
       // Remove from queue
-      var index = this._queryQueue.indexOf(query)
+      const index = this._queryQueue.indexOf(query)
       if (index > -1) {
         this._queryQueue.splice(index, 1)
       }
@@ -236,14 +236,14 @@ Client.prototype.query = function (config, values, callback) {
 
 // disconnect from the backend server
 Client.prototype.end = function (cb) {
-  var self = this
+  const self = this
 
   this._ending = true
 
   if (!this._connected) {
     this.once('connect', this.end.bind(this, cb))
   }
-  var result
+  let result
   if (!cb) {
     result = new this._Promise(function (resolve, reject) {
       cb = (err) => (err ? reject(err) : resolve())
@@ -271,7 +271,7 @@ Client.prototype._pulseQueryQueue = function (initialConnection) {
   if (this._hasActiveQuery()) {
     return
   }
-  var query = this._queryQueue.shift()
+  const query = this._queryQueue.shift()
   if (!query) {
     if (!initialConnection) {
       this.emit('drain')
@@ -280,7 +280,7 @@ Client.prototype._pulseQueryQueue = function (initialConnection) {
   }
   this._activeQuery = query
   query.submit(this)
-  var self = this
+  const self = this
   query.once('_done', function () {
     self._pulseQueryQueue()
   })
diff --git a/packages/pg/lib/native/query.js b/packages/pg/lib/native/query.js
index 0cfed1fda..e6d9296d1 100644
--- a/packages/pg/lib/native/query.js
+++ b/packages/pg/lib/native/query.js
@@ -1,10 +1,10 @@
 'use strict'
 
-var EventEmitter = require('events').EventEmitter
-var util = require('util')
-var utils = require('../utils')
+const EventEmitter = require('events').EventEmitter
+const util = require('util')
+const utils = require('../utils')
 
-var NativeQuery = (module.exports = function (config, values, callback) {
+const NativeQuery = (module.exports = function (config, values, callback) {
   EventEmitter.call(this)
   config = utils.normalizeQueryConfig(config, values, callback)
   this.text = config.text
@@ -31,7 +31,7 @@ var NativeQuery = (module.exports = function (config, values, callback) {
 
 util.inherits(NativeQuery, EventEmitter)
 
-var errorFieldMap = {
+const errorFieldMap = {
   /* eslint-disable quote-props */
   sqlState: 'code',
   statementPosition: 'position',
@@ -49,10 +49,10 @@ var errorFieldMap = {
 
 NativeQuery.prototype.handleError = function (err) {
   // copy pq error fields into the error object
-  var fields = this.native.pq.resultErrorFields()
+  const fields = this.native.pq.resultErrorFields()
   if (fields) {
-    for (var key in fields) {
-      var normalizedFieldName = errorFieldMap[key] || key
+    for (const key in fields) {
+      const normalizedFieldName = errorFieldMap[key] || key
       err[normalizedFieldName] = fields[key]
     }
   }
@@ -85,11 +85,11 @@ NativeQuery.prototype._getPromise = function () {
 
 NativeQuery.prototype.submit = function (client) {
   this.state = 'running'
-  var self = this
+  const self = this
   this.native = client.native
   client.native.arrayMode = this._arrayMode
 
-  var after = function (err, rows, results) {
+  let after = function (err, rows, results) {
     client.native.arrayMode = false
     setImmediate(function () {
       self.emit('_done')
@@ -136,7 +136,7 @@ NativeQuery.prototype.submit = function (client) {
       console.error('This can cause conflicts and silent errors executing queries')
       /* eslint-enable no-console */
     }
-    var values = (this.values || []).map(utils.prepareValue)
+    const values = (this.values || []).map(utils.prepareValue)
 
     // check if the client has already executed this named query
     // if so...just execute it again - skip the planning phase
@@ -158,7 +158,7 @@ NativeQuery.prototype.submit = function (client) {
       const err = new Error('Query values must be an array')
       return after(err)
     }
-    var vals = this.values.map(utils.prepareValue)
+    const vals = this.values.map(utils.prepareValue)
     client.native.query(this.text, vals, after)
   } else if (this.queryMode === 'extended') {
     client.native.query(this.text, [], after)
diff --git a/packages/pg/lib/result.js b/packages/pg/lib/result.js
index 98018a7d8..044ae7d36 100644
--- a/packages/pg/lib/result.js
+++ b/packages/pg/lib/result.js
@@ -1,8 +1,8 @@
 'use strict'
 
-var types = require('pg-types')
+const types = require('pg-types')
 
-var matchRegexp = /^([A-Za-z]+)(?: (\d+))?(?: (\d+))?/
+const matchRegexp = /^([A-Za-z]+)(?: (\d+))?(?: (\d+))?/
 
 // result object returned from query
 // in the 'end' event and also
@@ -26,7 +26,7 @@ class Result {
 
   // adds a command complete message
   addCommandComplete(msg) {
-    var match
+    let match
     if (msg.text) {
       // pure javascript
       match = matchRegexp.exec(msg.text)
@@ -48,9 +48,9 @@ class Result {
   }
 
   _parseRowAsArray(rowData) {
-    var row = new Array(rowData.length)
-    for (var i = 0, len = rowData.length; i < len; i++) {
-      var rawValue = rowData[i]
+    const row = new Array(rowData.length)
+    for (let i = 0, len = rowData.length; i < len; i++) {
+      const rawValue = rowData[i]
       if (rawValue !== null) {
         row[i] = this._parsers[i](rawValue)
       } else {
@@ -61,10 +61,10 @@ class Result {
   }
 
   parseRow(rowData) {
-    var row = { ...this._prebuiltEmptyResultObject }
-    for (var i = 0, len = rowData.length; i < len; i++) {
-      var rawValue = rowData[i]
-      var field = this.fields[i].name
+    const row = { ...this._prebuiltEmptyResultObject }
+    for (let i = 0, len = rowData.length; i < len; i++) {
+      const rawValue = rowData[i]
+      const field = this.fields[i].name
       if (rawValue !== null) {
         row[field] = this._parsers[i](rawValue)
       } else {
@@ -88,10 +88,10 @@ class Result {
       this._parsers = new Array(fieldDescriptions.length)
     }
 
-    var row = {}
+    const row = {}
 
-    for (var i = 0; i < fieldDescriptions.length; i++) {
-      var desc = fieldDescriptions[i]
+    for (let i = 0; i < fieldDescriptions.length; i++) {
+      const desc = fieldDescriptions[i]
       row[desc.name] = null
 
       if (this._types) {
diff --git a/packages/pg/lib/stream.js b/packages/pg/lib/stream.js
index cb0839878..2b09d71ee 100644
--- a/packages/pg/lib/stream.js
+++ b/packages/pg/lib/stream.js
@@ -24,7 +24,7 @@ function getNodejsStreamFuncs() {
   }
 
   function getSecureStream(options) {
-    var tls = require('tls')
+    const tls = require('tls')
     return tls.connect(options)
   }
   return {
diff --git a/packages/pg/lib/type-overrides.js b/packages/pg/lib/type-overrides.js
index 66693482b..9d219e525 100644
--- a/packages/pg/lib/type-overrides.js
+++ b/packages/pg/lib/type-overrides.js
@@ -1,6 +1,6 @@
 'use strict'
 
-var types = require('pg-types')
+const types = require('pg-types')
 
 function TypeOverrides(userTypes) {
   this._types = userTypes || types
diff --git a/packages/pg/lib/utils.js b/packages/pg/lib/utils.js
index 09b8d3dd8..35489b519 100644
--- a/packages/pg/lib/utils.js
+++ b/packages/pg/lib/utils.js
@@ -3,7 +3,7 @@
 const defaults = require('./defaults')
 
 function escapeElement(elementRepresentation) {
-  var escaped = elementRepresentation.replace(/\\/g, '\\\\').replace(/"/g, '\\"')
+  const escaped = elementRepresentation.replace(/\\/g, '\\\\').replace(/"/g, '\\"')
 
   return '"' + escaped + '"'
 }
@@ -12,8 +12,8 @@ function escapeElement(elementRepresentation) {
 // uses comma separator so won't work for types like box that use
 // a different array separator.
 function arrayString(val) {
-  var result = '{'
-  for (var i = 0; i < val.length; i++) {
+  let result = '{'
+  for (let i = 0; i < val.length; i++) {
     if (i > 0) {
       result = result + ','
     }
@@ -22,9 +22,9 @@ function arrayString(val) {
     } else if (Array.isArray(val[i])) {
       result = result + arrayString(val[i])
     } else if (ArrayBuffer.isView(val[i])) {
-      var item = val[i]
+      let item = val[i]
       if (!(item instanceof Buffer)) {
-        var buf = Buffer.from(item.buffer, item.byteOffset, item.byteLength)
+        const buf = Buffer.from(item.buffer, item.byteOffset, item.byteLength)
         if (buf.length === item.byteLength) {
           item = buf
         } else {
@@ -44,7 +44,7 @@ function arrayString(val) {
 // to their 'raw' counterparts for use as a postgres parameter
 // note: you can override this function to provide your own conversion mechanism
 // for complex types, etc...
-var prepareValue = function (val, seen) {
+const prepareValue = function (val, seen) {
   // null and undefined are both null for postgres
   if (val == null) {
     return null
@@ -53,7 +53,7 @@ var prepareValue = function (val, seen) {
     return val
   }
   if (ArrayBuffer.isView(val)) {
-    var buf = Buffer.from(val.buffer, val.byteOffset, val.byteLength)
+    const buf = Buffer.from(val.buffer, val.byteOffset, val.byteLength)
     if (buf.length === val.byteLength) {
       return buf
     }
@@ -97,13 +97,13 @@ function pad(number, digits) {
 }
 
 function dateToString(date) {
-  var offset = -date.getTimezoneOffset()
+  let offset = -date.getTimezoneOffset()
 
-  var year = date.getFullYear()
-  var isBCYear = year < 1
+  let year = date.getFullYear()
+  const isBCYear = year < 1
   if (isBCYear) year = Math.abs(year) + 1 // negative years are 1 off their BC representation
 
-  var ret =
+  let ret =
     pad(year, 4) +
     '-' +
     pad(date.getMonth() + 1, 2) +
@@ -131,11 +131,11 @@ function dateToString(date) {
 }
 
 function dateToStringUTC(date) {
-  var year = date.getUTCFullYear()
-  var isBCYear = year < 1
+  let year = date.getUTCFullYear()
+  const isBCYear = year < 1
   if (isBCYear) year = Math.abs(year) + 1 // negative years are 1 off their BC representation
 
-  var ret =
+  let ret =
     pad(year, 4) +
     '-' +
     pad(date.getUTCMonth() + 1, 2) +
@@ -177,11 +177,11 @@ const escapeIdentifier = function (str) {
 }
 
 const escapeLiteral = function (str) {
-  var hasBackslash = false
-  var escaped = "'"
+  let hasBackslash = false
+  let escaped = "'"
 
-  for (var i = 0; i < str.length; i++) {
-    var c = str[i]
+  for (let i = 0; i < str.length; i++) {
+    const c = str[i]
     if (c === "'") {
       escaped += c + c
     } else if (c === '\\') {
diff --git a/packages/pg/script/create-test-tables.js b/packages/pg/script/create-test-tables.js
index 622b0cd20..76ba2dbe4 100644
--- a/packages/pg/script/create-test-tables.js
+++ b/packages/pg/script/create-test-tables.js
@@ -1,8 +1,8 @@
 'use strict'
-var args = require('../test/cli')
-var pg = require('../lib')
+const args = require('../test/cli')
+const pg = require('../lib')
 
-var people = [
+const people = [
   { name: 'Aaron', age: 10 },
   { name: 'Brian', age: 20 },
   { name: 'Chris', age: 30 },
@@ -32,7 +32,7 @@ var people = [
 ]
 
 async function run() {
-  var con = new pg.Client({
+  const con = new pg.Client({
     user: args.user,
     password: args.password,
     host: args.host,
diff --git a/packages/pg/script/dump-db-types.js b/packages/pg/script/dump-db-types.js
index f76249483..46d1d1867 100644
--- a/packages/pg/script/dump-db-types.js
+++ b/packages/pg/script/dump-db-types.js
@@ -1,11 +1,11 @@
 'use strict'
-var pg = require('../lib')
-var args = require('../test/cli')
+const pg = require('../lib')
+const args = require('../test/cli')
 
-var queries = ['select CURRENT_TIMESTAMP', "select interval '1 day' + interval '1 hour'", "select TIMESTAMP 'today'"]
+const queries = ['select CURRENT_TIMESTAMP', "select interval '1 day' + interval '1 hour'", "select TIMESTAMP 'today'"]
 
 queries.forEach(function (query) {
-  var client = new pg.Client({
+  const client = new pg.Client({
     user: args.user,
     database: args.database,
     password: args.password,
diff --git a/packages/pg/test/buffer-list.js b/packages/pg/test/buffer-list.js
index ec48b6ad6..81985bace 100644
--- a/packages/pg/test/buffer-list.js
+++ b/packages/pg/test/buffer-list.js
@@ -3,7 +3,7 @@
 const BufferList = function () {
   this.buffers = []
 }
-var p = BufferList.prototype
+const p = BufferList.prototype
 
 p.add = function (buffer, front) {
   this.buffers[front ? 'unshift' : 'push'](buffer)
@@ -28,16 +28,16 @@ p.addInt32 = function (val, first) {
 }
 
 p.addCString = function (val, front) {
-  var len = Buffer.byteLength(val)
-  var buffer = Buffer.alloc(len + 1)
+  const len = Buffer.byteLength(val)
+  const buffer = Buffer.alloc(len + 1)
   buffer.write(val)
   buffer[len] = 0
   return this.add(buffer, front)
 }
 
 p.addString = function (val, front) {
-  var len = Buffer.byteLength(val)
-  var buffer = Buffer.alloc(len)
+  const len = Buffer.byteLength(val)
+  const buffer = Buffer.alloc(len)
   buffer.write(val)
   return this.add(buffer, front)
 }
@@ -47,7 +47,7 @@ p.addChar = function (char, first) {
 }
 
 p.join = function (appendLength, char) {
-  var length = this.getByteLength()
+  let length = this.getByteLength()
   if (appendLength) {
     this.addInt32(length + 4, true)
     return this.join(false, char)
@@ -56,8 +56,8 @@ p.join = function (appendLength, char) {
     this.addChar(char, true)
     length++
   }
-  var result = Buffer.alloc(length)
-  var index = 0
+  const result = Buffer.alloc(length)
+  let index = 0
   this.buffers.forEach(function (buffer) {
     buffer.copy(result, index, 0)
     index += buffer.length
@@ -66,8 +66,8 @@ p.join = function (appendLength, char) {
 }
 
 BufferList.concat = function () {
-  var total = new BufferList()
-  for (var i = 0; i < arguments.length; i++) {
+  const total = new BufferList()
+  for (let i = 0; i < arguments.length; i++) {
     total.add(arguments[i])
   }
   return total.join()
diff --git a/packages/pg/test/cli.js b/packages/pg/test/cli.js
index 03699b9ba..5bea4912c 100644
--- a/packages/pg/test/cli.js
+++ b/packages/pg/test/cli.js
@@ -1,8 +1,8 @@
 'use strict'
-var ConnectionParameters = require('../lib/connection-parameters')
-var config = new ConnectionParameters(process.argv[2])
+const ConnectionParameters = require('../lib/connection-parameters')
+const config = new ConnectionParameters(process.argv[2])
 
-for (var i = 0; i < process.argv.length; i++) {
+for (let i = 0; i < process.argv.length; i++) {
   switch (process.argv[i].toLowerCase()) {
     case 'native':
       config.native = true
diff --git a/packages/pg/test/integration/client/api-tests.js b/packages/pg/test/integration/client/api-tests.js
index 686eabb28..ab7ad6db8 100644
--- a/packages/pg/test/integration/client/api-tests.js
+++ b/packages/pg/test/integration/client/api-tests.js
@@ -1,9 +1,9 @@
 'use strict'
-var helper = require('../test-helper')
-var pg = helper.pg
+const helper = require('../test-helper')
+const pg = helper.pg
 const assert = require('assert')
 
-var suite = new helper.Suite()
+const suite = new helper.Suite()
 
 suite.test('null and undefined are both inserted as NULL', function (done) {
   const pool = new pg.Pool()
@@ -180,7 +180,7 @@ suite.test('executing nested queries', function (done) {
 })
 
 suite.test('raises error if cannot connect', function () {
-  var connectionString = 'pg://sfalsdkf:asdf@localhost/ieieie'
+  const connectionString = 'pg://sfalsdkf:asdf@localhost/ieieie'
   const pool = new pg.Pool({ connectionString: connectionString })
   pool.connect(
     assert.calls(function (err, client, done) {
@@ -213,7 +213,7 @@ suite.test('callback is fired once and only once', function (done) {
     assert.calls(function (err, client, release) {
       assert(!err)
       client.query('CREATE TEMP TABLE boom(name varchar(10))')
-      var callCount = 0
+      let callCount = 0
       client.query(
         [
           "INSERT INTO boom(name) VALUES('hai')",
@@ -256,7 +256,7 @@ suite.test('can provide callback and config and parameters', function (done) {
   pool.connect(
     assert.calls(function (err, client, release) {
       assert(!err)
-      var config = {
+      const config = {
         text: 'select $1::text as val',
       }
       client.query(
diff --git a/packages/pg/test/integration/client/appname-tests.js b/packages/pg/test/integration/client/appname-tests.js
index e69f805bf..b091a7835 100644
--- a/packages/pg/test/integration/client/appname-tests.js
+++ b/packages/pg/test/integration/client/appname-tests.js
@@ -1,24 +1,24 @@
 'use strict'
-var helper = require('./test-helper')
-var Client = helper.Client
+const helper = require('./test-helper')
+const Client = helper.Client
 const assert = require('assert')
 
-var suite = new helper.Suite()
+const suite = new helper.Suite()
 
-var conInfo = helper.config
+const conInfo = helper.config
 
 function getConInfo(override) {
   return Object.assign({}, conInfo, override)
 }
 
 function getAppName(conf, cb) {
-  var client = new Client(conf)
+  const client = new Client(conf)
   client.connect(
     assert.success(function () {
       client.query(
         'SHOW application_name',
         assert.success(function (res) {
-          var appName = res.rows[0].application_name
+          const appName = res.rows[0].application_name
           cb(appName)
           client.end()
         })
@@ -35,8 +35,8 @@ suite.test('No default appliation_name ', function (done) {
 })
 
 suite.test('fallback_application_name is used', function (done) {
-  var fbAppName = 'this is my app'
-  var conf = getConInfo({
+  const fbAppName = 'this is my app'
+  const conf = getConInfo({
     fallback_application_name: fbAppName,
   })
   getAppName(conf, function (res) {
@@ -46,8 +46,8 @@ suite.test('fallback_application_name is used', function (done) {
 })
 
 suite.test('application_name is used', function (done) {
-  var appName = 'some wired !@#$% application_name'
-  var conf = getConInfo({
+  const appName = 'some wired !@#$% application_name'
+  const conf = getConInfo({
     application_name: appName,
   })
   getAppName(conf, function (res) {
@@ -57,9 +57,9 @@ suite.test('application_name is used', function (done) {
 })
 
 suite.test('application_name has precedence over fallback_application_name', function (done) {
-  var appName = 'some wired !@#$% application_name'
-  var fbAppName = 'some other strange $$test$$ appname'
-  var conf = getConInfo({
+  const appName = 'some wired !@#$% application_name'
+  const fbAppName = 'some other strange $$test$$ appname'
+  const conf = getConInfo({
     application_name: appName,
     fallback_application_name: fbAppName,
   })
@@ -70,9 +70,9 @@ suite.test('application_name has precedence over fallback_application_name', fun
 })
 
 suite.test('application_name from connection string', function (done) {
-  var appName = 'my app'
-  var conParams = require('../../../lib/connection-parameters')
-  var conf
+  const appName = 'my app'
+  const conParams = require('../../../lib/connection-parameters')
+  let conf
   if (process.argv[2]) {
     conf = new conParams(process.argv[2] + '?application_name=' + appName)
   } else {
@@ -87,7 +87,7 @@ suite.test('application_name from connection string', function (done) {
 // TODO: make the test work for native client too
 if (!helper.args.native) {
   suite.test('application_name is read from the env', function (done) {
-    var appName = (process.env.PGAPPNAME = 'testest')
+    const appName = (process.env.PGAPPNAME = 'testest')
     getAppName({}, function (res) {
       delete process.env.PGAPPNAME
       assert.strictEqual(res, appName)
diff --git a/packages/pg/test/integration/client/array-tests.js b/packages/pg/test/integration/client/array-tests.js
index ce25bb778..24814be91 100644
--- a/packages/pg/test/integration/client/array-tests.js
+++ b/packages/pg/test/integration/client/array-tests.js
@@ -1,9 +1,9 @@
 'use strict'
-var helper = require('./test-helper')
-var pg = helper.pg
+const helper = require('./test-helper')
+const pg = helper.pg
 const assert = require('assert')
 
-var suite = new helper.Suite()
+const suite = new helper.Suite()
 
 const pool = new pg.Pool()
 
@@ -16,7 +16,7 @@ pool.connect(
         'SELECT $1::text[] as array',
         [[null]],
         assert.success(function (result) {
-          var array = result.rows[0].array
+          const array = result.rows[0].array
           assert.lengthIs(array, 1)
           assert.isNull(array[0])
           done()
@@ -25,9 +25,9 @@ pool.connect(
     })
 
     suite.test('elements containing JSON-escaped characters', function (done) {
-      var param = '\\"\\"'
+      let param = '\\"\\"'
 
-      for (var i = 1; i <= 0x1f; i++) {
+      for (let i = 1; i <= 0x1f; i++) {
         param += String.fromCharCode(i)
       }
 
@@ -35,7 +35,7 @@ pool.connect(
         'SELECT $1::text[] as array',
         [[param]],
         assert.success(function (result) {
-          var array = result.rows[0].array
+          const array = result.rows[0].array
           assert.lengthIs(array, 1)
           assert.equal(array[0], param)
           done()
@@ -70,7 +70,7 @@ pool.connect(
           client.query(
             'SELECT names FROM why',
             assert.success(function (result) {
-              var names = result.rows[0].names
+              const names = result.rows[0].names
               assert.lengthIs(names, 3)
               assert.equal(names[0], 'aaron')
               assert.equal(names[1], 'brian')
@@ -84,7 +84,7 @@ pool.connect(
           client.query(
             "SELECT '{}'::text[] as names",
             assert.success(function (result) {
-              var names = result.rows[0].names
+              const names = result.rows[0].names
               assert.lengthIs(names, 0)
               done()
             })
@@ -95,7 +95,7 @@ pool.connect(
           client.query(
             'SELECT \'{"joe,bob",jim}\'::text[] as names',
             assert.success(function (result) {
-              var names = result.rows[0].names
+              const names = result.rows[0].names
               assert.lengthIs(names, 2)
               assert.equal(names[0], 'joe,bob')
               assert.equal(names[1], 'jim')
@@ -108,7 +108,7 @@ pool.connect(
           client.query(
             'SELECT \'{"{","}"}\'::text[] as names',
             assert.success(function (result) {
-              var names = result.rows[0].names
+              const names = result.rows[0].names
               assert.lengthIs(names, 2)
               assert.equal(names[0], '{')
               assert.equal(names[1], '}')
@@ -121,7 +121,7 @@ pool.connect(
           client.query(
             'SELECT \'{joe,null,bob,"NULL"}\'::text[] as names',
             assert.success(function (result) {
-              var names = result.rows[0].names
+              const names = result.rows[0].names
               assert.lengthIs(names, 4)
               assert.equal(names[0], 'joe')
               assert.equal(names[1], null)
@@ -136,7 +136,7 @@ pool.connect(
           client.query(
             "SELECT ARRAY['joe''', 'jim', 'bob\"'] AS names",
             assert.success(function (result) {
-              var names = result.rows[0].names
+              const names = result.rows[0].names
               assert.lengthIs(names, 3)
               assert.equal(names[0], "joe'")
               assert.equal(names[1], 'jim')
@@ -150,7 +150,7 @@ pool.connect(
           client.query(
             "SELECT '{{1,joe},{2,bob}}'::text[] as names",
             assert.success(function (result) {
-              var names = result.rows[0].names
+              const names = result.rows[0].names
               assert.lengthIs(names, 2)
 
               assert.lengthIs(names[0], 2)
@@ -169,7 +169,7 @@ pool.connect(
           client.query(
             "SELECT '{1,2,3}'::integer[] as names",
             assert.success(function (result) {
-              var names = result.rows[0].names
+              const names = result.rows[0].names
               assert.lengthIs(names, 3)
               assert.equal(names[0], 1)
               assert.equal(names[1], 2)
@@ -183,7 +183,7 @@ pool.connect(
           client.query(
             "SELECT '{{1,100},{2,100},{3,100}}'::integer[] as names",
             assert.success(function (result) {
-              var names = result.rows[0].names
+              const names = result.rows[0].names
               assert.lengthIs(names, 3)
               assert.equal(names[0][0], 1)
               assert.equal(names[0][1], 100)
@@ -209,7 +209,7 @@ pool.connect(
               ],
             ],
             assert.success(function (result) {
-              var names = result.rows[0].names
+              const names = result.rows[0].names
               assert.lengthIs(names, 3)
               assert.equal(names[0][0], 1)
               assert.equal(names[0][1], 100)
diff --git a/packages/pg/test/integration/client/async-stack-trace-tests.js b/packages/pg/test/integration/client/async-stack-trace-tests.js
index 0baa03ea8..fd5b15da4 100644
--- a/packages/pg/test/integration/client/async-stack-trace-tests.js
+++ b/packages/pg/test/integration/client/async-stack-trace-tests.js
@@ -1,6 +1,6 @@
 'use strict'
-var helper = require('../test-helper')
-var pg = helper.pg
+const helper = require('../test-helper')
+const pg = helper.pg
 
 process.on('unhandledRejection', function (e) {
   console.error(e, e.stack)
diff --git a/packages/pg/test/integration/client/big-simple-query-tests.js b/packages/pg/test/integration/client/big-simple-query-tests.js
index a7e6770e8..3c50c1da1 100644
--- a/packages/pg/test/integration/client/big-simple-query-tests.js
+++ b/packages/pg/test/integration/client/big-simple-query-tests.js
@@ -1,6 +1,6 @@
 'use strict'
-var helper = require('./test-helper')
-var Query = helper.pg.Query
+const helper = require('./test-helper')
+const Query = helper.pg.Query
 const assert = require('assert')
 
 const suite = new helper.Suite()
@@ -13,13 +13,13 @@ const suite = new helper.Suite()
 */
 
 // Big query with a where clouse from supplied value
-var big_query_rows_1 = []
-var big_query_rows_2 = []
-var big_query_rows_3 = []
+const big_query_rows_1 = []
+const big_query_rows_2 = []
+const big_query_rows_3 = []
 
 // Works
 suite.test('big simple query 1', function (done) {
-  var client = helper.client()
+  const client = helper.client()
   client
     .query(
       new Query(
@@ -41,7 +41,7 @@ suite.test('big simple query 1', function (done) {
 
 // Works
 suite.test('big simple query 2', function (done) {
-  var client = helper.client()
+  const client = helper.client()
   client
     .query(
       new Query(
@@ -65,7 +65,7 @@ suite.test('big simple query 2', function (done) {
 // Fails most of the time with 'invalid byte sequence for encoding "UTF8": 0xb9' or 'insufficient data left in message'
 // If test 1 and 2 are commented out it works
 suite.test('big simple query 3', function (done) {
-  var client = helper.client()
+  const client = helper.client()
   client
     .query(
       new Query(
@@ -92,7 +92,7 @@ process.on('exit', function () {
   assert.equal(big_query_rows_3.length, 26, 'big simple query 3 should return 26 rows')
 })
 
-var runBigQuery = function (client) {
+const runBigQuery = function (client) {
   client.query(
     "select 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa' as bla from person where name = $1 or 1 = 1",
     [''],
@@ -107,8 +107,8 @@ var runBigQuery = function (client) {
 }
 
 suite.test('many times', function (done) {
-  var client = helper.client()
-  for (var i = 0; i < 20; i++) {
+  const client = helper.client()
+  for (let i = 0; i < 20; i++) {
     runBigQuery(client)
   }
   client.on('drain', function () {
diff --git a/packages/pg/test/integration/client/configuration-tests.js b/packages/pg/test/integration/client/configuration-tests.js
index a4b0790a6..a5a11560d 100644
--- a/packages/pg/test/integration/client/configuration-tests.js
+++ b/packages/pg/test/integration/client/configuration-tests.js
@@ -1,14 +1,14 @@
 'use strict'
-var helper = require('./test-helper')
-var pg = helper.pg
+const helper = require('./test-helper')
+const pg = helper.pg
 const assert = require('assert')
 const { Client } = helper
 
-var suite = new helper.Suite()
+const suite = new helper.Suite()
 
 // clear process.env
-var realEnv = {}
-for (var key in process.env) {
+const realEnv = {}
+for (const key in process.env) {
   realEnv[key] = process.env[key]
   if (!key.indexOf('PG')) delete process.env[key]
 }
@@ -30,7 +30,7 @@ suite.test('default values are used in new clients', function () {
     parseInputDatesAsUTC: false,
   })
 
-  var client = new pg.Client()
+  const client = new pg.Client()
   assert.same(client, {
     user: process.env.USER,
     password: null,
@@ -46,7 +46,7 @@ suite.test('modified values are passed to created clients', function () {
   pg.defaults.port = 1234
   pg.defaults.database = 'pow'
 
-  var client = new Client()
+  const client = new Client()
   assert.same(client, {
     user: 'boom',
     password: 'zap',
@@ -80,7 +80,7 @@ suite.test('database defaults to user when user is non-default', () => {
 
 suite.test('cleanup', () => {
   // restore process.env
-  for (var key in realEnv) {
+  for (const key in realEnv) {
     process.env[key] = realEnv[key]
   }
 })
diff --git a/packages/pg/test/integration/client/empty-query-tests.js b/packages/pg/test/integration/client/empty-query-tests.js
index 458a6f3a4..61d46512e 100644
--- a/packages/pg/test/integration/client/empty-query-tests.js
+++ b/packages/pg/test/integration/client/empty-query-tests.js
@@ -1,5 +1,5 @@
 'use strict'
-var helper = require('./test-helper')
+const helper = require('./test-helper')
 const suite = new helper.Suite()
 const assert = require('assert')
 
diff --git a/packages/pg/test/integration/client/error-handling-tests.js b/packages/pg/test/integration/client/error-handling-tests.js
index 0cf7dfabb..8a6fc667f 100644
--- a/packages/pg/test/integration/client/error-handling-tests.js
+++ b/packages/pg/test/integration/client/error-handling-tests.js
@@ -1,14 +1,14 @@
 'use strict'
 
-var helper = require('./test-helper')
+const helper = require('./test-helper')
 
-var pg = helper.pg
+const pg = helper.pg
 const assert = require('assert')
 const Client = pg.Client
 const DatabaseError = pg.DatabaseError
 
-var createErorrClient = function () {
-  var client = helper.client()
+const createErorrClient = function () {
+  const client = helper.client()
   client.once('error', function (err) {
     assert.fail('Client shoud not throw error during query execution')
   })
@@ -78,7 +78,7 @@ suite.test('using a client after closing it results in error', (done) => {
 })
 
 suite.test('query receives error on client shutdown', function (done) {
-  var client = new Client()
+  const client = new Client()
   client.connect(
     assert.success(function () {
       const config = {
@@ -102,8 +102,8 @@ suite.test('query receives error on client shutdown', function (done) {
   )
 })
 
-var ensureFuture = function (testClient, done) {
-  var goodQuery = testClient.query(new pg.Query('select age from boom'))
+const ensureFuture = function (testClient, done) {
+  const goodQuery = testClient.query(new pg.Query('select age from boom'))
   assert.emits(goodQuery, 'row', function (row) {
     assert.equal(row.age, 28)
     done()
@@ -111,12 +111,12 @@ var ensureFuture = function (testClient, done) {
 }
 
 suite.test('when query is parsing', (done) => {
-  var client = createErorrClient()
+  const client = createErorrClient()
 
   client.query({ text: 'CREATE TEMP TABLE boom(age integer); INSERT INTO boom (age) VALUES (28);' })
 
   // this query wont parse since there isn't a table named bang
-  var query = client.query(
+  const query = client.query(
     new pg.Query({
       text: 'select * from bang where name = $1',
       values: ['0'],
@@ -129,11 +129,11 @@ suite.test('when query is parsing', (done) => {
 })
 
 suite.test('when a query is binding', function (done) {
-  var client = createErorrClient()
+  const client = createErorrClient()
 
   client.query({ text: 'CREATE TEMP TABLE boom(age integer); INSERT INTO boom (age) VALUES (28);' })
 
-  var query = client.query(
+  const query = client.query(
     new pg.Query({
       text: 'select * from boom where age = $1',
       values: ['asldkfjasdf'],
@@ -150,7 +150,7 @@ suite.test('when a query is binding', function (done) {
 })
 
 suite.test('non-query error with callback', function (done) {
-  var client = new Client({
+  const client = new Client({
     user: 'asldkfjsadlfkj',
   })
   client.connect(
@@ -162,7 +162,7 @@ suite.test('non-query error with callback', function (done) {
 })
 
 suite.test('non-error calls supplied callback', function (done) {
-  var client = new Client({
+  const client = new Client({
     user: helper.args.user,
     password: helper.args.password,
     host: helper.args.host,
@@ -179,7 +179,7 @@ suite.test('non-error calls supplied callback', function (done) {
 })
 
 suite.test('when connecting to an invalid host with callback', function (done) {
-  var client = new Client({
+  const client = new Client({
     user: 'very invalid username',
   })
   client.on('error', () => {
@@ -192,7 +192,7 @@ suite.test('when connecting to an invalid host with callback', function (done) {
 })
 
 suite.test('when connecting to invalid host with promise', function (done) {
-  var client = new Client({
+  const client = new Client({
     user: 'very invalid username',
   })
   client.on('error', () => {
@@ -202,7 +202,7 @@ suite.test('when connecting to invalid host with promise', function (done) {
 })
 
 suite.test('non-query error', function (done) {
-  var client = new Client({
+  const client = new Client({
     user: 'asldkfjsadlfkj',
   })
   client.connect().catch((e) => {
@@ -212,9 +212,9 @@ suite.test('non-query error', function (done) {
 })
 
 suite.test('within a simple query', (done) => {
-  var client = createErorrClient()
+  const client = createErorrClient()
 
-  var query = client.query(new pg.Query("select eeeee from yodas_dsflsd where pixistix = 'zoiks!!!'"))
+  const query = client.query(new pg.Query("select eeeee from yodas_dsflsd where pixistix = 'zoiks!!!'"))
 
   assert.emits(query, 'error', function (error) {
     if (!helper.config.native) {
diff --git a/packages/pg/test/integration/client/field-name-escape-tests.js b/packages/pg/test/integration/client/field-name-escape-tests.js
index 146ad1b68..4261c198e 100644
--- a/packages/pg/test/integration/client/field-name-escape-tests.js
+++ b/packages/pg/test/integration/client/field-name-escape-tests.js
@@ -1,8 +1,8 @@
-var pg = require('./test-helper').pg
+const pg = require('./test-helper').pg
 
-var sql = 'SELECT 1 AS "\\\'/*", 2 AS "\\\'*/\n + process.exit(-1)] = null;\n//"'
+const sql = 'SELECT 1 AS "\\\'/*", 2 AS "\\\'*/\n + process.exit(-1)] = null;\n//"'
 
-var client = new pg.Client()
+const client = new pg.Client()
 client.connect()
 client.query(sql, function (err, res) {
   if (err) throw err
diff --git a/packages/pg/test/integration/client/huge-numeric-tests.js b/packages/pg/test/integration/client/huge-numeric-tests.js
index 719e9b428..fd4c28295 100644
--- a/packages/pg/test/integration/client/huge-numeric-tests.js
+++ b/packages/pg/test/integration/client/huge-numeric-tests.js
@@ -1,11 +1,11 @@
 'use strict'
-var helper = require('./test-helper')
+const helper = require('./test-helper')
 const pool = new helper.pg.Pool()
 const assert = require('assert')
 
 pool.connect(
   assert.success(function (client, done) {
-    var types = require('pg-types')
+    const types = require('pg-types')
     // 1231 = numericOID
     types.setTypeParser(1700, function () {
       return 'yes'
@@ -13,7 +13,7 @@ pool.connect(
     types.setTypeParser(1700, 'binary', function () {
       return 'yes'
     })
-    var bignum = '294733346389144765940638005275322203805'
+    const bignum = '294733346389144765940638005275322203805'
     client.query('CREATE TEMP TABLE bignumz(id numeric)')
     client.query('INSERT INTO bignumz(id) VALUES ($1)', [bignum])
     client.query(
diff --git a/packages/pg/test/integration/client/idle_in_transaction_session_timeout-tests.js b/packages/pg/test/integration/client/idle_in_transaction_session_timeout-tests.js
index 1e327492f..933542600 100644
--- a/packages/pg/test/integration/client/idle_in_transaction_session_timeout-tests.js
+++ b/packages/pg/test/integration/client/idle_in_transaction_session_timeout-tests.js
@@ -1,18 +1,18 @@
 'use strict'
-var helper = require('./test-helper')
-var Client = helper.Client
+const helper = require('./test-helper')
+const Client = helper.Client
 const assert = require('assert')
 
-var suite = new helper.Suite()
+const suite = new helper.Suite()
 
-var conInfo = helper.config
+const conInfo = helper.config
 
 function getConInfo(override) {
   return Object.assign({}, conInfo, override)
 }
 
 function testClientVersion(cb) {
-  var client = new Client({})
+  const client = new Client({})
   client.connect(
     assert.success(function () {
       helper.versionGTE(
@@ -37,13 +37,13 @@ function testClientVersion(cb) {
 }
 
 function getIdleTransactionSessionTimeout(conf, cb) {
-  var client = new Client(conf)
+  const client = new Client(conf)
   client.connect(
     assert.success(function () {
       client.query(
         'SHOW idle_in_transaction_session_timeout',
         assert.success(function (res) {
-          var timeout = res.rows[0].idle_in_transaction_session_timeout
+          const timeout = res.rows[0].idle_in_transaction_session_timeout
           cb(timeout)
           client.end()
         })
@@ -64,7 +64,7 @@ if (!helper.args.native) {
     })
 
     suite.test('idle_in_transaction_session_timeout integer is used', function (done) {
-      var conf = getConInfo({
+      const conf = getConInfo({
         idle_in_transaction_session_timeout: 3000,
       })
       getIdleTransactionSessionTimeout(conf, function (res) {
@@ -74,7 +74,7 @@ if (!helper.args.native) {
     })
 
     suite.test('idle_in_transaction_session_timeout float is used', function (done) {
-      var conf = getConInfo({
+      const conf = getConInfo({
         idle_in_transaction_session_timeout: 3000.7,
       })
       getIdleTransactionSessionTimeout(conf, function (res) {
@@ -84,7 +84,7 @@ if (!helper.args.native) {
     })
 
     suite.test('idle_in_transaction_session_timeout string is used', function (done) {
-      var conf = getConInfo({
+      const conf = getConInfo({
         idle_in_transaction_session_timeout: '3000',
       })
       getIdleTransactionSessionTimeout(conf, function (res) {
diff --git a/packages/pg/test/integration/client/json-type-parsing-tests.js b/packages/pg/test/integration/client/json-type-parsing-tests.js
index ba7696020..c5882e9d8 100644
--- a/packages/pg/test/integration/client/json-type-parsing-tests.js
+++ b/packages/pg/test/integration/client/json-type-parsing-tests.js
@@ -1,6 +1,6 @@
 'use strict'
-var helper = require('./test-helper')
-var assert = require('assert')
+const helper = require('./test-helper')
+const assert = require('assert')
 
 const pool = new helper.pg.Pool()
 pool.connect(
@@ -15,14 +15,14 @@ pool.connect(
           return pool.end()
         }
         client.query('CREATE TEMP TABLE stuff(id SERIAL PRIMARY KEY, data JSON)')
-        var value = { name: 'Brian', age: 250, alive: true, now: new Date() }
+        const value = { name: 'Brian', age: 250, alive: true, now: new Date() }
         client.query('INSERT INTO stuff (data) VALUES ($1)', [value])
         client.query(
           'SELECT * FROM stuff',
           assert.success(function (result) {
             assert.equal(result.rows.length, 1)
             assert.equal(typeof result.rows[0].data, 'object')
-            var row = result.rows[0].data
+            const row = result.rows[0].data
             assert.strictEqual(row.name, value.name)
             assert.strictEqual(row.age, value.age)
             assert.strictEqual(row.alive, value.alive)
diff --git a/packages/pg/test/integration/client/network-partition-tests.js b/packages/pg/test/integration/client/network-partition-tests.js
index 589ae123b..6ebdb8b45 100644
--- a/packages/pg/test/integration/client/network-partition-tests.js
+++ b/packages/pg/test/integration/client/network-partition-tests.js
@@ -1,12 +1,12 @@
 'use strict'
-var buffers = require('../../test-buffers')
-var helper = require('./test-helper')
-var suite = new helper.Suite()
+const buffers = require('../../test-buffers')
+const helper = require('./test-helper')
+const suite = new helper.Suite()
 const assert = require('assert')
 
-var net = require('net')
+const net = require('net')
 
-var Server = function (response) {
+const Server = function (response) {
   this.server = undefined
   this.socket = undefined
   this.response = response
@@ -58,11 +58,11 @@ Server.prototype.close = function (cb) {
   this.server.close(cb)
 }
 
-var testServer = function (server, cb) {
+const testServer = function (server, cb) {
   // wait for our server to start
   server.start(function (options) {
     // connect a client to it
-    var client = new helper.Client(options)
+    const client = new helper.Client(options)
     client.connect().catch((err) => {
       assert(err instanceof Error)
       clearTimeout(timeoutId)
@@ -77,7 +77,7 @@ var testServer = function (server, cb) {
     })
 
     // blow up if we don't receive an error
-    var timeoutId = setTimeout(function () {
+    const timeoutId = setTimeout(function () {
       throw new Error('Client should have emitted an error but it did not.')
     }, 5000)
   })
diff --git a/packages/pg/test/integration/client/no-data-tests.js b/packages/pg/test/integration/client/no-data-tests.js
index 382b6ffd0..bf61d6d13 100644
--- a/packages/pg/test/integration/client/no-data-tests.js
+++ b/packages/pg/test/integration/client/no-data-tests.js
@@ -1,10 +1,10 @@
 'use strict'
-var helper = require('./test-helper')
+const helper = require('./test-helper')
 const suite = new helper.Suite()
 const assert = require('assert')
 
 suite.test('noData message handling', function () {
-  var client = helper.client()
+  const client = helper.client()
 
   client.query({
     name: 'boom',
@@ -37,7 +37,7 @@ suite.test('noData message handling', function () {
       values: [101],
     },
     (err, res) => {
-      var row = res.rows[0]
+      const row = res.rows[0]
       assert.strictEqual(row.size, 100)
     }
   )
diff --git a/packages/pg/test/integration/client/no-row-result-tests.js b/packages/pg/test/integration/client/no-row-result-tests.js
index fa84f1d0a..d53470040 100644
--- a/packages/pg/test/integration/client/no-row-result-tests.js
+++ b/packages/pg/test/integration/client/no-row-result-tests.js
@@ -1,12 +1,12 @@
 'use strict'
-var helper = require('./test-helper')
-var pg = helper.pg
+const helper = require('./test-helper')
+const pg = helper.pg
 const suite = new helper.Suite()
 const pool = new pg.Pool()
 const assert = require('assert')
 
 suite.test('can access results when no rows are returned', function (done) {
-  var checkResult = function (result) {
+  const checkResult = function (result) {
     assert(result.fields, 'should have fields definition')
     assert.equal(result.fields.length, 1)
     assert.equal(result.fields[0].name, 'val')
@@ -16,7 +16,7 @@ suite.test('can access results when no rows are returned', function (done) {
   pool.connect(
     assert.success(function (client, release) {
       const q = new pg.Query('select $1::text as val limit 0', ['hi'])
-      var query = client.query(
+      const query = client.query(
         q,
         assert.success(function (result) {
           checkResult(result)
diff --git a/packages/pg/test/integration/client/parse-int-8-tests.js b/packages/pg/test/integration/client/parse-int-8-tests.js
index 150ee7bbd..114fd8227 100644
--- a/packages/pg/test/integration/client/parse-int-8-tests.js
+++ b/packages/pg/test/integration/client/parse-int-8-tests.js
@@ -1,7 +1,7 @@
 'use strict'
 
-var helper = require('../test-helper')
-var pg = helper.pg
+const helper = require('../test-helper')
+const pg = helper.pg
 const suite = new helper.Suite()
 const assert = require('assert')
 
diff --git a/packages/pg/test/integration/client/prepared-statement-tests.js b/packages/pg/test/integration/client/prepared-statement-tests.js
index 0d01007af..9047eae6c 100644
--- a/packages/pg/test/integration/client/prepared-statement-tests.js
+++ b/packages/pg/test/integration/client/prepared-statement-tests.js
@@ -1,18 +1,18 @@
 'use strict'
-var helper = require('./test-helper')
-var Query = helper.pg.Query
+const helper = require('./test-helper')
+const Query = helper.pg.Query
 
 const assert = require('assert')
-var suite = new helper.Suite()
+const suite = new helper.Suite()
 
 ;(function () {
-  var client = helper.client()
+  const client = helper.client()
   client.on('drain', client.end.bind(client))
 
-  var queryName = 'user by age and like name'
+  const queryName = 'user by age and like name'
 
   suite.test('first named prepared statement', function (done) {
-    var query = client.query(
+    const query = client.query(
       new Query({
         text: 'select name from person where age <= $1 and name LIKE $2',
         values: [20, 'Bri%'],
@@ -28,7 +28,7 @@ var suite = new helper.Suite()
   })
 
   suite.test('second named prepared statement with same name & text', function (done) {
-    var cachedQuery = client.query(
+    const cachedQuery = client.query(
       new Query({
         text: 'select name from person where age <= $1 and name LIKE $2',
         name: queryName,
@@ -44,7 +44,7 @@ var suite = new helper.Suite()
   })
 
   suite.test('with same name, but without query text', function (done) {
-    var q = client.query(
+    const q = client.query(
       new Query({
         name: queryName,
         values: [30, '%n%'],
@@ -81,12 +81,12 @@ var suite = new helper.Suite()
   })
 })()
 ;(function () {
-  var statementName = 'differ'
-  var statement1 = 'select count(*)::int4 as count from person'
-  var statement2 = 'select count(*)::int4 as count from person where age < $1'
+  const statementName = 'differ'
+  const statement1 = 'select count(*)::int4 as count from person'
+  const statement2 = 'select count(*)::int4 as count from person where age < $1'
 
-  var client1 = helper.client()
-  var client2 = helper.client()
+  const client1 = helper.client()
+  const client2 = helper.client()
 
   suite.test('client 1 execution', function (done) {
     client1.query(
@@ -103,7 +103,7 @@ var suite = new helper.Suite()
   })
 
   suite.test('client 2 execution', function (done) {
-    var query = client2.query(
+    const query = client2.query(
       new Query({
         name: statementName,
         text: statement2,
@@ -125,13 +125,13 @@ var suite = new helper.Suite()
   })
 })()
 ;(function () {
-  var client = helper.client()
+  const client = helper.client()
   client.query('CREATE TEMP TABLE zoom(name varchar(100));')
   client.query("INSERT INTO zoom (name) VALUES ('zed')")
   client.query("INSERT INTO zoom (name) VALUES ('postgres')")
   client.query("INSERT INTO zoom (name) VALUES ('node postgres')")
 
-  var checkForResults = function (q) {
+  const checkForResults = function (q) {
     assert.emits(q, 'row', function (row) {
       assert.equal(row.name, 'node postgres')
 
@@ -146,7 +146,7 @@ var suite = new helper.Suite()
   }
 
   suite.test('with small row count', function (done) {
-    var query = client.query(
+    const query = client.query(
       new Query(
         {
           name: 'get names',
@@ -161,7 +161,7 @@ var suite = new helper.Suite()
   })
 
   suite.test('with large row count', function (done) {
-    var query = client.query(
+    const query = client.query(
       new Query(
         {
           name: 'get names',
diff --git a/packages/pg/test/integration/client/query-as-promise-tests.js b/packages/pg/test/integration/client/query-as-promise-tests.js
index beb17b12e..8e1ba5c71 100644
--- a/packages/pg/test/integration/client/query-as-promise-tests.js
+++ b/packages/pg/test/integration/client/query-as-promise-tests.js
@@ -1,7 +1,7 @@
 'use strict'
-var bluebird = require('bluebird')
-var helper = require('../test-helper')
-var pg = helper.pg
+const bluebird = require('bluebird')
+const helper = require('../test-helper')
+const pg = helper.pg
 const assert = require('assert')
 
 process.on('unhandledRejection', function (e) {
diff --git a/packages/pg/test/integration/client/query-column-names-tests.js b/packages/pg/test/integration/client/query-column-names-tests.js
index fe537a928..d64e876b8 100644
--- a/packages/pg/test/integration/client/query-column-names-tests.js
+++ b/packages/pg/test/integration/client/query-column-names-tests.js
@@ -1,6 +1,6 @@
 'use strict'
-var helper = require('../test-helper')
-var pg = helper.pg
+const helper = require('../test-helper')
+const pg = helper.pg
 const assert = require('assert')
 
 new helper.Suite().test('support for complex column names', function () {
diff --git a/packages/pg/test/integration/client/query-error-handling-prepared-statement-tests.js b/packages/pg/test/integration/client/query-error-handling-prepared-statement-tests.js
index 6b8af7008..13ecf4b53 100644
--- a/packages/pg/test/integration/client/query-error-handling-prepared-statement-tests.js
+++ b/packages/pg/test/integration/client/query-error-handling-prepared-statement-tests.js
@@ -1,24 +1,24 @@
 'use strict'
-var helper = require('./test-helper')
-var Query = helper.pg.Query
+const helper = require('./test-helper')
+const Query = helper.pg.Query
 const { Client } = helper
 const assert = require('assert')
 
-var suite = new helper.Suite()
+const suite = new helper.Suite()
 
 suite.test('client end during query execution of prepared statement', function (done) {
-  var client = new Client()
+  const client = new Client()
   client.connect(
     assert.success(function () {
-      var sleepQuery = 'select pg_sleep($1)'
+      const sleepQuery = 'select pg_sleep($1)'
 
-      var queryConfig = {
+      const queryConfig = {
         name: 'sleep query',
         text: sleepQuery,
         values: [5],
       }
 
-      var queryInstance = new Query(
+      const queryInstance = new Query(
         queryConfig,
         assert.calls(function (err, result) {
           assert.equal(err.message, 'Connection terminated')
@@ -26,7 +26,7 @@ suite.test('client end during query execution of prepared statement', function (
         })
       )
 
-      var query1 = client.query(queryInstance)
+      const query1 = client.query(queryInstance)
 
       query1.on('error', function (err) {
         assert.fail('Prepared statement should not emit error')
@@ -46,9 +46,9 @@ suite.test('client end during query execution of prepared statement', function (
 })
 
 function killIdleQuery(targetQuery, cb) {
-  var client2 = new Client(helper.args)
-  var pidColName = 'procpid'
-  var queryColName = 'current_query'
+  const client2 = new Client(helper.args)
+  let pidColName = 'procpid'
+  let queryColName = 'current_query'
   client2.connect(
     assert.success(function () {
       helper.versionGTE(
@@ -59,7 +59,7 @@ function killIdleQuery(targetQuery, cb) {
             pidColName = 'pid'
             queryColName = 'query'
           }
-          var killIdleQuery =
+          const killIdleQuery =
             'SELECT ' +
             pidColName +
             ', (SELECT pg_terminate_backend(' +
@@ -87,10 +87,10 @@ suite.test('query killed during query execution of prepared statement', function
   if (helper.args.native) {
     return done()
   }
-  var client = new Client(helper.args)
+  const client = new Client(helper.args)
   client.connect(
     assert.success(function () {
-      var sleepQuery = 'select pg_sleep($1)'
+      const sleepQuery = 'select pg_sleep($1)'
 
       const queryConfig = {
         name: 'sleep query',
@@ -101,7 +101,7 @@ suite.test('query killed during query execution of prepared statement', function
       // client should emit an error because it is unexpectedly disconnected
       assert.emits(client, 'error')
 
-      var query1 = client.query(
+      const query1 = client.query(
         new Query(queryConfig),
         assert.calls(function (err, result) {
           assert.equal(err.message, 'terminating connection due to administrator command')
diff --git a/packages/pg/test/integration/client/query-error-handling-tests.js b/packages/pg/test/integration/client/query-error-handling-tests.js
index c7af6bda9..eaceec03e 100644
--- a/packages/pg/test/integration/client/query-error-handling-tests.js
+++ b/packages/pg/test/integration/client/query-error-handling-tests.js
@@ -1,19 +1,19 @@
 'use strict'
-var helper = require('./test-helper')
-var Query = helper.pg.Query
-var DatabaseError = helper.pg.DatabaseError
+const helper = require('./test-helper')
+const Query = helper.pg.Query
+const DatabaseError = helper.pg.DatabaseError
 const assert = require('assert')
 const { Client } = helper
 const suite = new helper.Suite()
 
 suite.test('error during query execution', function () {
-  var client = new Client(helper.args)
+  const client = new Client(helper.args)
   client.connect(
     assert.success(function () {
-      var queryText = 'select pg_sleep(10)'
-      var sleepQuery = new Query(queryText)
-      var pidColName = 'procpid'
-      var queryColName = 'current_query'
+      const queryText = 'select pg_sleep(10)'
+      const sleepQuery = new Query(queryText)
+      let pidColName = 'procpid'
+      let queryColName = 'current_query'
       helper.versionGTE(
         client,
         90200,
@@ -22,7 +22,7 @@ suite.test('error during query execution', function () {
             pidColName = 'pid'
             queryColName = 'query'
           }
-          var query1 = client.query(
+          const query1 = client.query(
             sleepQuery,
             assert.calls(function (err, result) {
               assert(err)
@@ -36,10 +36,10 @@ suite.test('error during query execution', function () {
             assert.fail('Query with an error should not emit "end" event')
           })
           setTimeout(function () {
-            var client2 = new Client(helper.args)
+            const client2 = new Client(helper.args)
             client2.connect(
               assert.success(function () {
-                var killIdleQuery = `SELECT ${pidColName}, (SELECT pg_cancel_backend(${pidColName})) AS killed FROM pg_stat_activity WHERE ${queryColName} LIKE $1`
+                const killIdleQuery = `SELECT ${pidColName}, (SELECT pg_cancel_backend(${pidColName})) AS killed FROM pg_stat_activity WHERE ${queryColName} LIKE $1`
                 client2.query(
                   killIdleQuery,
                   [queryText],
@@ -64,7 +64,7 @@ if (helper.config.native) {
 }
 
 suite.test('9.3 column error fields', function () {
-  var client = new Client(helper.args)
+  const client = new Client(helper.args)
   client.connect(
     assert.success(function () {
       helper.versionGTE(
@@ -93,7 +93,7 @@ suite.test('9.3 column error fields', function () {
 })
 
 suite.test('9.3 constraint error fields', function () {
-  var client = new Client(helper.args)
+  const client = new Client(helper.args)
   client.connect(
     assert.success(function () {
       helper.versionGTE(
diff --git a/packages/pg/test/integration/client/quick-disconnect-tests.js b/packages/pg/test/integration/client/quick-disconnect-tests.js
index 066411fc8..8c14214da 100644
--- a/packages/pg/test/integration/client/quick-disconnect-tests.js
+++ b/packages/pg/test/integration/client/quick-disconnect-tests.js
@@ -1,8 +1,8 @@
 'use strict'
 // test for issue #320
 //
-var helper = require('./test-helper')
+const helper = require('./test-helper')
 
-var client = new helper.pg.Client(helper.config)
+const client = new helper.pg.Client(helper.config)
 client.connect()
 client.end()
diff --git a/packages/pg/test/integration/client/result-metadata-tests.js b/packages/pg/test/integration/client/result-metadata-tests.js
index fbd375ece..fe6eaf919 100644
--- a/packages/pg/test/integration/client/result-metadata-tests.js
+++ b/packages/pg/test/integration/client/result-metadata-tests.js
@@ -1,6 +1,6 @@
 'use strict'
-var helper = require('./test-helper')
-var pg = helper.pg
+const helper = require('./test-helper')
+const pg = helper.pg
 const assert = require('assert')
 
 const pool = new pg.Pool()
diff --git a/packages/pg/test/integration/client/results-as-array-tests.js b/packages/pg/test/integration/client/results-as-array-tests.js
index 3e30e9796..3e2a36ad9 100644
--- a/packages/pg/test/integration/client/results-as-array-tests.js
+++ b/packages/pg/test/integration/client/results-as-array-tests.js
@@ -1,16 +1,16 @@
 'use strict'
-var util = require('util')
-var helper = require('./test-helper')
+const util = require('util')
+const helper = require('./test-helper')
 const assert = require('assert')
 const suite = new helper.Suite()
 
-var Client = helper.Client
+const Client = helper.Client
 
-var conInfo = helper.config
+const conInfo = helper.config
 
 suite.test('returns results as array', function () {
-  var client = new Client(conInfo)
-  var checkRow = function (row) {
+  const client = new Client(conInfo)
+  const checkRow = function (row) {
     assert(util.isArray(row), 'row should be an array')
     assert.equal(row.length, 4)
     assert.equal(row[0].getFullYear(), new Date().getFullYear())
@@ -20,7 +20,7 @@ suite.test('returns results as array', function () {
   }
   client.connect(
     assert.success(function () {
-      var config = {
+      const config = {
         text: 'SELECT NOW(), 1::int, $1::text, null',
         values: ['hai'],
         rowMode: 'array',
diff --git a/packages/pg/test/integration/client/row-description-on-results-tests.js b/packages/pg/test/integration/client/row-description-on-results-tests.js
index deb9a212d..728e0b96f 100644
--- a/packages/pg/test/integration/client/row-description-on-results-tests.js
+++ b/packages/pg/test/integration/client/row-description-on-results-tests.js
@@ -1,16 +1,16 @@
 'use strict'
-var helper = require('./test-helper')
+const helper = require('./test-helper')
 const assert = require('assert')
 const suite = new helper.Suite()
 
-var Client = helper.Client
+const Client = helper.Client
 
-var conInfo = helper.config
+const conInfo = helper.config
 
-var checkResult = function (result) {
+const checkResult = function (result) {
   assert(result.fields)
   assert.equal(result.fields.length, 3)
-  var fields = result.fields
+  const fields = result.fields
   assert.equal(fields[0].name, 'now')
   assert.equal(fields[1].name, 'num')
   assert.equal(fields[2].name, 'texty')
@@ -20,7 +20,7 @@ var checkResult = function (result) {
 }
 
 suite.test('row descriptions on result object', function () {
-  var client = new Client(conInfo)
+  const client = new Client(conInfo)
   client.connect(
     assert.success(function () {
       client.query(
@@ -36,7 +36,7 @@ suite.test('row descriptions on result object', function () {
 })
 
 suite.test('row description on no rows', function () {
-  var client = new Client(conInfo)
+  const client = new Client(conInfo)
   client.connect(
     assert.success(function () {
       client.query(
diff --git a/packages/pg/test/integration/client/simple-query-tests.js b/packages/pg/test/integration/client/simple-query-tests.js
index 93d859bd3..f5f834432 100644
--- a/packages/pg/test/integration/client/simple-query-tests.js
+++ b/packages/pg/test/integration/client/simple-query-tests.js
@@ -1,28 +1,28 @@
 'use strict'
-var helper = require('./test-helper')
-var Query = helper.pg.Query
+const helper = require('./test-helper')
+const Query = helper.pg.Query
 const assert = require('assert')
 const suite = new helper.Suite()
 const test = suite.test.bind(suite)
 
 // before running this test make sure you run the script create-test-tables
 test('simple query interface', function () {
-  var client = helper.client()
+  const client = helper.client()
 
-  var query = client.query(new Query('select name from person order by name collate "C"'))
+  const query = client.query(new Query('select name from person order by name collate "C"'))
 
   client.on('drain', client.end.bind(client))
 
-  var rows = []
+  const rows = []
   query.on('row', function (row, result) {
     assert.ok(result)
     rows.push(row['name'])
   })
   query.once('row', function (row) {
     test('Can iterate through columns', function () {
-      var columnCount = 0
+      let columnCount = 0
       // eslint-disable-next-line @typescript-eslint/no-unused-vars
-      for (var column in row) {
+      for (const column in row) {
         columnCount++
       }
       if ('length' in row) {
@@ -47,11 +47,11 @@ test('simple query interface', function () {
 })
 
 test('prepared statements do not mutate params', function () {
-  var client = helper.client()
+  const client = helper.client()
 
-  var params = [1]
+  const params = [1]
 
-  var query = client.query(new Query('select name from person where $1 = 1 order by name collate "C"', params))
+  const query = client.query(new Query('select name from person where $1 = 1 order by name collate "C"', params))
 
   assert.deepEqual(params, [1])
 
@@ -72,10 +72,10 @@ test('prepared statements do not mutate params', function () {
 })
 
 test('multiple simple queries', function () {
-  var client = helper.client()
+  const client = helper.client()
   client.query({ text: "create temp table bang(id serial, name varchar(5));insert into bang(name) VALUES('boom');" })
   client.query("insert into bang(name) VALUES ('yes');")
-  var query = client.query(new Query('select name from bang'))
+  const query = client.query(new Query('select name from bang'))
   assert.emits(query, 'row', function (row) {
     assert.equal(row['name'], 'boom')
     assert.emits(query, 'row', function (row) {
@@ -86,12 +86,12 @@ test('multiple simple queries', function () {
 })
 
 test('multiple select statements', function () {
-  var client = helper.client()
+  const client = helper.client()
   client.query(
     'create temp table boom(age integer); insert into boom(age) values(1); insert into boom(age) values(2); insert into boom(age) values(3)'
   )
   client.query({ text: "create temp table bang(name varchar(5)); insert into bang(name) values('zoom');" })
-  var result = client.query(new Query({ text: 'select age from boom where age < 2; select name from bang' }))
+  const result = client.query(new Query({ text: 'select age from boom where age < 2; select name from bang' }))
   assert.emits(result, 'row', function (row) {
     assert.strictEqual(row['age'], 1)
     assert.emits(result, 'row', function (row) {
diff --git a/packages/pg/test/integration/client/statement_timeout-tests.js b/packages/pg/test/integration/client/statement_timeout-tests.js
index fc67a7c4a..b45c71fcc 100644
--- a/packages/pg/test/integration/client/statement_timeout-tests.js
+++ b/packages/pg/test/integration/client/statement_timeout-tests.js
@@ -1,24 +1,24 @@
 'use strict'
-var helper = require('./test-helper')
-var Client = helper.Client
+const helper = require('./test-helper')
+const Client = helper.Client
 
 const assert = require('assert')
-var suite = new helper.Suite()
+const suite = new helper.Suite()
 
-var conInfo = helper.config
+const conInfo = helper.config
 
 function getConInfo(override) {
   return Object.assign({}, conInfo, override)
 }
 
 function getStatementTimeout(conf, cb) {
-  var client = new Client(conf)
+  const client = new Client(conf)
   client.connect(
     assert.success(function () {
       client.query(
         'SHOW statement_timeout',
         assert.success(function (res) {
-          var statementTimeout = res.rows[0].statement_timeout
+          const statementTimeout = res.rows[0].statement_timeout
           cb(statementTimeout)
           client.end()
         })
@@ -38,7 +38,7 @@ if (!helper.args.native) {
   })
 
   suite.test('statement_timeout integer is used', function (done) {
-    var conf = getConInfo({
+    const conf = getConInfo({
       statement_timeout: 3000,
     })
     getStatementTimeout(conf, function (res) {
@@ -48,7 +48,7 @@ if (!helper.args.native) {
   })
 
   suite.test('statement_timeout float is used', function (done) {
-    var conf = getConInfo({
+    const conf = getConInfo({
       statement_timeout: 3000.7,
     })
     getStatementTimeout(conf, function (res) {
@@ -58,7 +58,7 @@ if (!helper.args.native) {
   })
 
   suite.test('statement_timeout string is used', function (done) {
-    var conf = getConInfo({
+    const conf = getConInfo({
       statement_timeout: '3000',
     })
     getStatementTimeout(conf, function (res) {
@@ -68,10 +68,10 @@ if (!helper.args.native) {
   })
 
   suite.test('statement_timeout actually cancels long running queries', function (done) {
-    var conf = getConInfo({
+    const conf = getConInfo({
       statement_timeout: '10', // 10ms to keep tests running fast
     })
-    var client = new Client(conf)
+    const client = new Client(conf)
     client.connect(
       assert.success(function () {
         client.query('SELECT pg_sleep( 1 )', function (error) {
diff --git a/packages/pg/test/integration/client/test-helper.js b/packages/pg/test/integration/client/test-helper.js
index 14f8134eb..c915ce09b 100644
--- a/packages/pg/test/integration/client/test-helper.js
+++ b/packages/pg/test/integration/client/test-helper.js
@@ -1,4 +1,4 @@
 'use strict'
-var helper = require('./../test-helper')
+const helper = require('./../test-helper')
 
 module.exports = helper
diff --git a/packages/pg/test/integration/client/timezone-tests.js b/packages/pg/test/integration/client/timezone-tests.js
index f00599087..df87dcc74 100644
--- a/packages/pg/test/integration/client/timezone-tests.js
+++ b/packages/pg/test/integration/client/timezone-tests.js
@@ -1,11 +1,11 @@
 'use strict'
-var helper = require('./../test-helper')
+const helper = require('./../test-helper')
 const assert = require('assert')
 
-var oldTz = process.env.TZ
+const oldTz = process.env.TZ
 process.env.TZ = 'Europe/Berlin'
 
-var date = new Date()
+const date = new Date()
 
 const pool = new helper.pg.Pool()
 const suite = new helper.Suite()
diff --git a/packages/pg/test/integration/client/transaction-tests.js b/packages/pg/test/integration/client/transaction-tests.js
index 11cffe24c..feb178fef 100644
--- a/packages/pg/test/integration/client/transaction-tests.js
+++ b/packages/pg/test/integration/client/transaction-tests.js
@@ -1,5 +1,5 @@
 'use strict'
-var helper = require('./test-helper')
+const helper = require('./test-helper')
 const suite = new helper.Suite()
 const pg = helper.pg
 const assert = require('assert')
@@ -9,7 +9,7 @@ client.connect(
   assert.success(function () {
     client.query('begin')
 
-    var getZed = {
+    const getZed = {
       text: 'SELECT * FROM person WHERE name = $1',
       values: ['Zed'],
     }
diff --git a/packages/pg/test/integration/client/type-coercion-tests.js b/packages/pg/test/integration/client/type-coercion-tests.js
index 587a28c61..705ff0946 100644
--- a/packages/pg/test/integration/client/type-coercion-tests.js
+++ b/packages/pg/test/integration/client/type-coercion-tests.js
@@ -1,10 +1,10 @@
 'use strict'
-var helper = require('./test-helper')
-var pg = helper.pg
+const helper = require('./test-helper')
+const pg = helper.pg
 const suite = new helper.Suite()
 const assert = require('assert')
 
-var testForTypeCoercion = function (type) {
+const testForTypeCoercion = function (type) {
   const pool = new pg.Pool()
   suite.test(`test type coercion ${type.name}`, (cb) => {
     pool.connect(function (err, client, done) {
@@ -23,7 +23,7 @@ var testForTypeCoercion = function (type) {
               })
             )
 
-            var query = client.query(
+            const query = client.query(
               new pg.Query({
                 name: 'get type ' + type.name,
                 text: 'select col from test_type',
@@ -39,8 +39,8 @@ var testForTypeCoercion = function (type) {
               query,
               'row',
               function (row) {
-                var expected = val + ' (' + typeof val + ')'
-                var returned = row.col + ' (' + typeof row.col + ')'
+                const expected = val + ' (' + typeof val + ')'
+                const returned = row.col + ' (' + typeof row.col + ')'
                 assert.strictEqual(row.col, val, 'expected ' + type.name + ' of ' + expected + ' but got ' + returned)
               },
               'row should have been called for ' + type.name + ' of ' + val
@@ -59,7 +59,7 @@ var testForTypeCoercion = function (type) {
   })
 }
 
-var types = [
+let types = [
   {
     name: 'integer',
     values: [-2147483648, -1, 0, 1, 2147483647, null],
@@ -141,15 +141,15 @@ types.forEach(function (type) {
 })
 
 suite.test('timestamptz round trip', function (cb) {
-  var now = new Date()
-  var client = helper.client()
+  const now = new Date()
+  const client = helper.client()
   client.query('create temp table date_tests(name varchar(10), tstz timestamptz(3))')
   client.query({
     text: 'insert into date_tests(name, tstz)VALUES($1, $2)',
     name: 'add date',
     values: ['now', now],
   })
-  var result = client.query(
+  const result = client.query(
     new pg.Query({
       name: 'get date',
       text: 'select * from date_tests where name = $1',
@@ -158,7 +158,7 @@ suite.test('timestamptz round trip', function (cb) {
   )
 
   assert.emits(result, 'row', function (row) {
-    var date = row.tstz
+    const date = row.tstz
     assert.equal(date.getYear(), now.getYear())
     assert.equal(date.getMonth(), now.getMonth())
     assert.equal(date.getDate(), now.getDate())
@@ -196,7 +196,7 @@ suite.test('selecting nulls', (cb) => {
 })
 
 suite.test('date range extremes', function (done) {
-  var client = helper.client()
+  const client = helper.client()
 
   // Set the server timeszone to the same as used for the test,
   // otherwise (if server's timezone is ahead of GMT) in
diff --git a/packages/pg/test/integration/client/type-parser-override-tests.js b/packages/pg/test/integration/client/type-parser-override-tests.js
index 5f7216ad6..883e61bad 100644
--- a/packages/pg/test/integration/client/type-parser-override-tests.js
+++ b/packages/pg/test/integration/client/type-parser-override-tests.js
@@ -1,9 +1,9 @@
 'use strict'
-var helper = require('./test-helper')
+const helper = require('./test-helper')
 const assert = require('assert')
 
 function testTypeParser(client, expectedResult, done) {
-  var boolValue = true
+  const boolValue = true
   client.query('CREATE TEMP TABLE parserOverrideTest(id bool)')
   client.query('INSERT INTO parserOverrideTest(id) VALUES ($1)', [boolValue])
   client.query(
@@ -20,7 +20,7 @@ pool.connect(
   assert.success(function (client1, done1) {
     pool.connect(
       assert.success(function (client2, done2) {
-        var boolTypeOID = 16
+        const boolTypeOID = 16
         client1.setTypeParser(boolTypeOID, function () {
           return 'first client'
         })
diff --git a/packages/pg/test/integration/connection-pool/connection-pool-size-tests.js b/packages/pg/test/integration/connection-pool/connection-pool-size-tests.js
index 2d16fe49f..260e922d3 100644
--- a/packages/pg/test/integration/connection-pool/connection-pool-size-tests.js
+++ b/packages/pg/test/integration/connection-pool/connection-pool-size-tests.js
@@ -11,7 +11,7 @@ const testPoolSize = function (max) {
     let count = 0
 
     return new Promise((resolve) => {
-      for (var i = 0; i < max; i++) {
+      for (let i = 0; i < max; i++) {
         pool.connect(function (err, client, release) {
           assert(!err)
           client.query('SELECT * FROM NOW()')
diff --git a/packages/pg/test/integration/connection-pool/error-tests.js b/packages/pg/test/integration/connection-pool/error-tests.js
index 9f20aa4e6..d5857b583 100644
--- a/packages/pg/test/integration/connection-pool/error-tests.js
+++ b/packages/pg/test/integration/connection-pool/error-tests.js
@@ -1,5 +1,5 @@
 'use strict'
-var helper = require('./test-helper')
+const helper = require('./test-helper')
 const pg = helper.pg
 const native = helper.args.native
 const assert = require('assert')
@@ -23,9 +23,9 @@ suite.test('errors emitted on checked-out clients', (cb) => {
               client2,
               90200,
               assert.success(function (isGreater) {
-                var killIdleQuery =
+                let killIdleQuery =
                   'SELECT pid, (SELECT pg_terminate_backend(pid)) AS killed FROM pg_stat_activity WHERE state = $1'
-                var params = ['idle']
+                let params = ['idle']
                 if (!isGreater) {
                   killIdleQuery =
                     'SELECT procpid, (SELECT pg_terminate_backend(procpid)) AS killed FROM pg_stat_activity WHERE current_query LIKE $1'
diff --git a/packages/pg/test/integration/connection-pool/idle-timeout-tests.js b/packages/pg/test/integration/connection-pool/idle-timeout-tests.js
index 2bfe8e409..bc67f856f 100644
--- a/packages/pg/test/integration/connection-pool/idle-timeout-tests.js
+++ b/packages/pg/test/integration/connection-pool/idle-timeout-tests.js
@@ -1,5 +1,5 @@
 'use strict'
-var helper = require('./test-helper')
+const helper = require('./test-helper')
 const assert = require('assert')
 
 new helper.Suite().test('idle timeout', function () {
diff --git a/packages/pg/test/integration/connection-pool/native-instance-tests.js b/packages/pg/test/integration/connection-pool/native-instance-tests.js
index 8cd494e72..6f713411d 100644
--- a/packages/pg/test/integration/connection-pool/native-instance-tests.js
+++ b/packages/pg/test/integration/connection-pool/native-instance-tests.js
@@ -1,10 +1,10 @@
 'use strict'
-var helper = require('./../test-helper')
-var pg = helper.pg
-var native = helper.args.native
+const helper = require('./../test-helper')
+const pg = helper.pg
+const native = helper.args.native
 const assert = require('assert')
 
-var pool = new pg.Pool()
+const pool = new pg.Pool()
 
 pool.connect(
   assert.calls(function (err, client, done) {
diff --git a/packages/pg/test/integration/connection-pool/test-helper.js b/packages/pg/test/integration/connection-pool/test-helper.js
index 14f8134eb..c915ce09b 100644
--- a/packages/pg/test/integration/connection-pool/test-helper.js
+++ b/packages/pg/test/integration/connection-pool/test-helper.js
@@ -1,4 +1,4 @@
 'use strict'
-var helper = require('./../test-helper')
+const helper = require('./../test-helper')
 
 module.exports = helper
diff --git a/packages/pg/test/integration/connection-pool/yield-support-tests.js b/packages/pg/test/integration/connection-pool/yield-support-tests.js
index cc3d270d6..d3b33cc21 100644
--- a/packages/pg/test/integration/connection-pool/yield-support-tests.js
+++ b/packages/pg/test/integration/connection-pool/yield-support-tests.js
@@ -1,17 +1,17 @@
 'use strict'
-var helper = require('./test-helper')
-var co = require('co')
+const helper = require('./test-helper')
+const co = require('co')
 const assert = require('assert')
 
 const pool = new helper.pg.Pool()
 new helper.Suite().test(
   'using coroutines works with promises',
   co.wrap(function* () {
-    var client = yield pool.connect()
-    var res = yield client.query('SELECT $1::text as name', ['foo'])
+    const client = yield pool.connect()
+    const res = yield client.query('SELECT $1::text as name', ['foo'])
     assert.equal(res.rows[0].name, 'foo')
 
-    var threw = false
+    let threw = false
     try {
       yield client.query('SELECT LKDSJDSLKFJ')
     } catch (e) {
diff --git a/packages/pg/test/integration/domain-tests.js b/packages/pg/test/integration/domain-tests.js
index 78c7663e8..ae63a4a8e 100644
--- a/packages/pg/test/integration/domain-tests.js
+++ b/packages/pg/test/integration/domain-tests.js
@@ -1,8 +1,8 @@
 'use strict'
 
-var helper = require('./test-helper')
-var Query = helper.pg.Query
-var suite = new helper.Suite()
+const helper = require('./test-helper')
+const Query = helper.pg.Query
+const suite = new helper.Suite()
 
 const assert = require('assert')
 const Pool = helper.pg.Pool
@@ -22,9 +22,9 @@ suite.test('no domain', function (cb) {
 suite.test('with domain', function (cb) {
   assert(!process.domain)
   const pool = new Pool()
-  var domain = require('domain').create()
+  const domain = require('domain').create()
   domain.run(function () {
-    var startingDomain = process.domain
+    const startingDomain = process.domain
     assert(startingDomain)
     pool.connect(
       assert.success(function (client, done) {
@@ -46,7 +46,7 @@ suite.test('with domain', function (cb) {
 })
 
 suite.test('error on domain', function (cb) {
-  var domain = require('domain').create()
+  const domain = require('domain').create()
   const pool = new Pool()
   domain.on('error', function () {
     pool.end(cb)
diff --git a/packages/pg/test/integration/gh-issues/130-tests.js b/packages/pg/test/integration/gh-issues/130-tests.js
index 00aae4208..88c4dfb79 100644
--- a/packages/pg/test/integration/gh-issues/130-tests.js
+++ b/packages/pg/test/integration/gh-issues/130-tests.js
@@ -1,6 +1,6 @@
 'use strict'
-var helper = require('../test-helper')
-var exec = require('child_process').exec
+const helper = require('../test-helper')
+const exec = require('child_process').exec
 const assert = require('assert')
 
 helper.pg.defaults.poolIdleTimeout = 1000
@@ -14,8 +14,8 @@ pool.connect(function (err, client, done) {
   })
   client.query('SELECT pg_backend_pid()', function (err, result) {
     assert.ifError(err)
-    var pid = result.rows[0].pg_backend_pid
-    var psql = 'psql'
+    const pid = result.rows[0].pg_backend_pid
+    let psql = 'psql'
     if (helper.args.host) psql = psql + ' -h ' + helper.args.host
     if (helper.args.port) psql = psql + ' -p ' + helper.args.port
     if (helper.args.user) psql = psql + ' -U ' + helper.args.user
diff --git a/packages/pg/test/integration/gh-issues/131-tests.js b/packages/pg/test/integration/gh-issues/131-tests.js
index b169849c1..b2144e6f4 100644
--- a/packages/pg/test/integration/gh-issues/131-tests.js
+++ b/packages/pg/test/integration/gh-issues/131-tests.js
@@ -1,9 +1,9 @@
 'use strict'
-var helper = require('../test-helper')
-var pg = helper.pg
+const helper = require('../test-helper')
+const pg = helper.pg
 const assert = require('assert')
 
-var suite = new helper.Suite()
+const suite = new helper.Suite()
 
 suite.test('parsing array decimal results', function (done) {
   const pool = new pg.Pool()
diff --git a/packages/pg/test/integration/gh-issues/1382-tests.js b/packages/pg/test/integration/gh-issues/1382-tests.js
index e80924c64..ea2a60f77 100644
--- a/packages/pg/test/integration/gh-issues/1382-tests.js
+++ b/packages/pg/test/integration/gh-issues/1382-tests.js
@@ -1,5 +1,5 @@
 'use strict'
-var helper = require('./../test-helper')
+const helper = require('./../test-helper')
 
 const suite = new helper.Suite()
 
diff --git a/packages/pg/test/integration/gh-issues/1854-tests.js b/packages/pg/test/integration/gh-issues/1854-tests.js
index 92ac6ec35..6e345f4cf 100644
--- a/packages/pg/test/integration/gh-issues/1854-tests.js
+++ b/packages/pg/test/integration/gh-issues/1854-tests.js
@@ -1,5 +1,5 @@
 'use strict'
-var helper = require('./../test-helper')
+const helper = require('./../test-helper')
 
 const suite = new helper.Suite()
 
diff --git a/packages/pg/test/integration/gh-issues/199-tests.js b/packages/pg/test/integration/gh-issues/199-tests.js
index 78d4cd32b..10246eb98 100644
--- a/packages/pg/test/integration/gh-issues/199-tests.js
+++ b/packages/pg/test/integration/gh-issues/199-tests.js
@@ -1,12 +1,12 @@
 'use strict'
-var helper = require('../test-helper')
-var client = helper.client()
+const helper = require('../test-helper')
+const client = helper.client()
 const assert = require('assert')
 
 client.query('CREATE TEMP TABLE arrtest (n integer, s varchar)')
 client.query("INSERT INTO arrtest VALUES (4, 'foo'), (5, 'bar'), (6, 'baz');")
 
-var qText =
+const qText =
   "SELECT \
 ARRAY[1, 2, 3] AS b,\
 ARRAY['xx', 'yy', 'zz'] AS c,\
@@ -15,8 +15,8 @@ ARRAY(SELECT s FROM arrtest) AS e;"
 
 client.query(qText, function (err, result) {
   if (err) throw err
-  var row = result.rows[0]
-  for (var key in row) {
+  const row = result.rows[0]
+  for (const key in row) {
     assert.equal(typeof row[key], 'object')
     assert.equal(row[key].length, 3)
   }
diff --git a/packages/pg/test/integration/gh-issues/2056-tests.js b/packages/pg/test/integration/gh-issues/2056-tests.js
index 2a12678b9..cf1be338f 100644
--- a/packages/pg/test/integration/gh-issues/2056-tests.js
+++ b/packages/pg/test/integration/gh-issues/2056-tests.js
@@ -1,6 +1,6 @@
 'use strict'
-var helper = require('./../test-helper')
-var assert = require('assert')
+const helper = require('./../test-helper')
+const assert = require('assert')
 
 const suite = new helper.Suite()
 
diff --git a/packages/pg/test/integration/gh-issues/2079-tests.js b/packages/pg/test/integration/gh-issues/2079-tests.js
index ad1c82aac..5c31b83d2 100644
--- a/packages/pg/test/integration/gh-issues/2079-tests.js
+++ b/packages/pg/test/integration/gh-issues/2079-tests.js
@@ -1,11 +1,11 @@
 'use strict'
-var helper = require('./../test-helper')
-var assert = require('assert')
+const helper = require('./../test-helper')
+const assert = require('assert')
 
 const suite = new helper.Suite()
 
 // makes a backend server that responds with a non 'S' ssl response buffer
-let makeTerminatingBackend = (byte) => {
+const makeTerminatingBackend = (byte) => {
   const { createServer } = require('net')
 
   const server = createServer((socket) => {
diff --git a/packages/pg/test/integration/gh-issues/2085-tests.js b/packages/pg/test/integration/gh-issues/2085-tests.js
index 2536bba82..d71c55c0d 100644
--- a/packages/pg/test/integration/gh-issues/2085-tests.js
+++ b/packages/pg/test/integration/gh-issues/2085-tests.js
@@ -1,6 +1,6 @@
 'use strict'
-var helper = require('./../test-helper')
-var assert = require('assert')
+const helper = require('./../test-helper')
+const assert = require('assert')
 
 const suite = new helper.Suite()
 
diff --git a/packages/pg/test/integration/gh-issues/2108-tests.js b/packages/pg/test/integration/gh-issues/2108-tests.js
index cbf2caabd..648b0df52 100644
--- a/packages/pg/test/integration/gh-issues/2108-tests.js
+++ b/packages/pg/test/integration/gh-issues/2108-tests.js
@@ -1,5 +1,5 @@
 'use strict'
-var helper = require('./../test-helper')
+const helper = require('./../test-helper')
 const suite = new helper.Suite()
 
 suite.test('Closing an unconnected client calls callback', (done) => {
diff --git a/packages/pg/test/integration/gh-issues/2556-tests.js b/packages/pg/test/integration/gh-issues/2556-tests.js
index 13fdf80eb..7ba0a0ade 100644
--- a/packages/pg/test/integration/gh-issues/2556-tests.js
+++ b/packages/pg/test/integration/gh-issues/2556-tests.js
@@ -1,15 +1,15 @@
 'use strict'
-var helper = require('./../test-helper')
-var assert = require('assert')
+const helper = require('./../test-helper')
+const assert = require('assert')
 
-var callbackError = new Error('TEST: Throw in callback')
+const callbackError = new Error('TEST: Throw in callback')
 
 const suite = new helper.Suite()
 
 suite.test('it should cleanup client even if an error is thrown in a callback', (done) => {
   // temporarily replace the test framework's uncaughtException handlers
   // with a custom one that ignores the callbackError
-  let original_handlers = process.listeners('uncaughtException')
+  const original_handlers = process.listeners('uncaughtException')
   process.removeAllListeners('uncaughtException')
   process.on('uncaughtException', (err) => {
     if (err != callbackError) {
@@ -18,7 +18,7 @@ suite.test('it should cleanup client even if an error is thrown in a callback',
   })
 
   // throw an error in a callback and verify that a subsequent query works without error
-  var client = helper.client()
+  const client = helper.client()
   client.query('SELECT NOW()', (err) => {
     assert(!err)
     setTimeout(reuseClient, 50)
@@ -30,7 +30,7 @@ suite.test('it should cleanup client even if an error is thrown in a callback',
       assert(!err)
 
       // restore the test framework's uncaughtException handlers
-      for (let handler of original_handlers) {
+      for (const handler of original_handlers) {
         process.on('uncaughtException', handler)
       }
 
diff --git a/packages/pg/test/integration/gh-issues/3062-tests.js b/packages/pg/test/integration/gh-issues/3062-tests.js
index 76cee2952..325bcf9a4 100644
--- a/packages/pg/test/integration/gh-issues/3062-tests.js
+++ b/packages/pg/test/integration/gh-issues/3062-tests.js
@@ -1,6 +1,6 @@
 'use strict'
 const helper = require('../test-helper')
-var assert = require('assert')
+const assert = require('assert')
 const suite = new helper.Suite()
 
 // https://github.com/brianc/node-postgres/issues/3062
diff --git a/packages/pg/test/integration/gh-issues/507-tests.js b/packages/pg/test/integration/gh-issues/507-tests.js
index 19fa67f62..1486bcd34 100644
--- a/packages/pg/test/integration/gh-issues/507-tests.js
+++ b/packages/pg/test/integration/gh-issues/507-tests.js
@@ -1,6 +1,6 @@
 'use strict'
-var helper = require('../test-helper')
-var pg = helper.pg
+const helper = require('../test-helper')
+const pg = helper.pg
 const assert = require('assert')
 
 new helper.Suite().test('parsing array results', function (cb) {
diff --git a/packages/pg/test/integration/gh-issues/600-tests.js b/packages/pg/test/integration/gh-issues/600-tests.js
index 586db151a..f477e8499 100644
--- a/packages/pg/test/integration/gh-issues/600-tests.js
+++ b/packages/pg/test/integration/gh-issues/600-tests.js
@@ -1,10 +1,10 @@
 'use strict'
-var async = require('async')
-var helper = require('../test-helper')
+const async = require('async')
+const helper = require('../test-helper')
 const suite = new helper.Suite()
 const assert = require('assert')
 
-var db = helper.client()
+const db = helper.client()
 
 function createTableFoo(callback) {
   db.query('create temp table foo(column1 int, column2 int)', callback)
@@ -55,7 +55,7 @@ function doTransaction(callback) {
   })
 }
 
-var steps = [createTableFoo, createTableBar, doTransaction, insertDataBar]
+const steps = [createTableFoo, createTableBar, doTransaction, insertDataBar]
 
 suite.test('test if query fails', function (done) {
   async.series(
@@ -68,8 +68,8 @@ suite.test('test if query fails', function (done) {
 })
 
 suite.test('test if prepare works but bind fails', function (done) {
-  var client = helper.client()
-  var q = {
+  const client = helper.client()
+  const q = {
     text: 'SELECT $1::int as name',
     values: ['brian'],
     name: 'test',
diff --git a/packages/pg/test/integration/gh-issues/675-tests.js b/packages/pg/test/integration/gh-issues/675-tests.js
index 2e281ecc6..8517fdbef 100644
--- a/packages/pg/test/integration/gh-issues/675-tests.js
+++ b/packages/pg/test/integration/gh-issues/675-tests.js
@@ -1,19 +1,19 @@
 'use strict'
-var helper = require('../test-helper')
-var assert = require('assert')
+const helper = require('../test-helper')
+const assert = require('assert')
 
 const pool = new helper.pg.Pool()
 pool.connect(function (err, client, done) {
   if (err) throw err
 
-  var c = 'CREATE TEMP TABLE posts (body TEXT)'
+  let c = 'CREATE TEMP TABLE posts (body TEXT)'
 
   client.query(c, function (err) {
     if (err) throw err
 
     c = 'INSERT INTO posts (body) VALUES ($1) RETURNING *'
 
-    var body = Buffer.from('foo')
+    let body = Buffer.from('foo')
     client.query(c, [body], function (err) {
       if (err) throw err
 
diff --git a/packages/pg/test/integration/gh-issues/699-tests.js b/packages/pg/test/integration/gh-issues/699-tests.js
index 6ec99a5c9..7af83b8fd 100644
--- a/packages/pg/test/integration/gh-issues/699-tests.js
+++ b/packages/pg/test/integration/gh-issues/699-tests.js
@@ -1,6 +1,6 @@
 'use strict'
-var helper = require('../test-helper')
-var copyFrom = require('pg-copy-streams').from
+const helper = require('../test-helper')
+const copyFrom = require('pg-copy-streams').from
 
 if (helper.args.native) return
 
@@ -8,12 +8,12 @@ const pool = new helper.pg.Pool()
 pool.connect(function (err, client, done) {
   if (err) throw err
 
-  var c = 'CREATE TEMP TABLE employee (id integer, fname varchar(400), lname varchar(400))'
+  const c = 'CREATE TEMP TABLE employee (id integer, fname varchar(400), lname varchar(400))'
 
   client.query(c, function (err) {
     if (err) throw err
 
-    var stream = client.query(copyFrom('COPY employee FROM STDIN'))
+    const stream = client.query(copyFrom('COPY employee FROM STDIN'))
     stream.on('end', function () {
       done()
       setTimeout(() => {
@@ -21,8 +21,8 @@ pool.connect(function (err, client, done) {
       }, 50)
     })
 
-    for (var i = 1; i <= 5; i++) {
-      var line = ['1\ttest', i, '\tuser', i, '\n']
+    for (let i = 1; i <= 5; i++) {
+      const line = ['1\ttest', i, '\tuser', i, '\n']
       stream.write(line.join(''))
     }
     stream.end()
diff --git a/packages/pg/test/integration/gh-issues/787-tests.js b/packages/pg/test/integration/gh-issues/787-tests.js
index 510e5a7ae..5d518475b 100644
--- a/packages/pg/test/integration/gh-issues/787-tests.js
+++ b/packages/pg/test/integration/gh-issues/787-tests.js
@@ -1,9 +1,9 @@
 'use strict'
-var helper = require('../test-helper')
+const helper = require('../test-helper')
 const pool = new helper.pg.Pool()
 
 pool.connect(function (err, client) {
-  var q = {
+  const q = {
     name: 'This is a super long query name just so I can test that an error message is properly spit out to console.error without throwing an exception or anything',
     text: 'SELECT NOW()',
   }
diff --git a/packages/pg/test/integration/gh-issues/882-tests.js b/packages/pg/test/integration/gh-issues/882-tests.js
index 4a8ef6474..17d7aafcf 100644
--- a/packages/pg/test/integration/gh-issues/882-tests.js
+++ b/packages/pg/test/integration/gh-issues/882-tests.js
@@ -1,7 +1,7 @@
 'use strict'
 // client should not hang on an empty query
-var helper = require('../test-helper')
-var client = helper.client()
+const helper = require('../test-helper')
+const client = helper.client()
 client.query({ name: 'foo1', text: null })
 client.query({ name: 'foo2', text: '   ' })
 client.query({ name: 'foo3', text: '' }, function (err, res) {
diff --git a/packages/pg/test/integration/gh-issues/981-tests.js b/packages/pg/test/integration/gh-issues/981-tests.js
index 998adea3a..68cfb0b1f 100644
--- a/packages/pg/test/integration/gh-issues/981-tests.js
+++ b/packages/pg/test/integration/gh-issues/981-tests.js
@@ -1,17 +1,17 @@
 'use strict'
-var helper = require('./../test-helper')
+const helper = require('./../test-helper')
 
 //native bindings are only installed for native tests
 if (!helper.args.native) {
   return
 }
 
-var assert = require('assert')
-var pg = require('../../../lib')
-var native = require('../../../lib').native
+const assert = require('assert')
+const pg = require('../../../lib')
+const native = require('../../../lib').native
 
-var JsClient = require('../../../lib/client')
-var NativeClient = require('../../../lib/native')
+const JsClient = require('../../../lib/client')
+const NativeClient = require('../../../lib/native')
 
 assert(pg.Client === JsClient)
 assert(native.Client === NativeClient)
diff --git a/packages/pg/test/integration/test-helper.js b/packages/pg/test/integration/test-helper.js
index 654b2f745..631acbae3 100644
--- a/packages/pg/test/integration/test-helper.js
+++ b/packages/pg/test/integration/test-helper.js
@@ -1,5 +1,5 @@
 'use strict'
-var helper = require('./../test-helper')
+const helper = require('./../test-helper')
 let { Client } = helper
 const assert = require('assert')
 
@@ -11,7 +11,7 @@ if (helper.args.native) {
 
 // creates a client from cli parameters
 helper.client = function (cb) {
-  var client = new Client()
+  const client = new Client()
   client.connect(cb)
   return client
 }
@@ -21,7 +21,7 @@ helper.versionGTE = function (client, testVersion, callback) {
     'SHOW server_version_num',
     assert.calls(function (err, result) {
       if (err) return callback(err)
-      var version = parseInt(result.rows[0].server_version_num, 10)
+      const version = parseInt(result.rows[0].server_version_num, 10)
       return callback(null, version >= testVersion)
     })
   )
diff --git a/packages/pg/test/native/callback-api-tests.js b/packages/pg/test/native/callback-api-tests.js
index 8ee5e69d7..d129e4a24 100644
--- a/packages/pg/test/native/callback-api-tests.js
+++ b/packages/pg/test/native/callback-api-tests.js
@@ -1,12 +1,12 @@
 'use strict'
-var domain = require('domain')
-var helper = require('./../test-helper')
-var Client = require('./../../lib/native')
+const domain = require('domain')
+const helper = require('./../test-helper')
+const Client = require('./../../lib/native')
 const suite = new helper.Suite()
 const assert = require('assert')
 
 suite.test('fires callback with results', function (done) {
-  var client = new Client(helper.config)
+  const client = new Client(helper.config)
   client.connect()
   client.query(
     'SELECT 1 as num',
@@ -28,10 +28,10 @@ suite.test('fires callback with results', function (done) {
 })
 
 suite.test('preserves domain', function (done) {
-  var dom = domain.create()
+  const dom = domain.create()
 
   dom.run(function () {
-    var client = new Client(helper.config)
+    const client = new Client(helper.config)
     assert.ok(dom === require('domain').active, 'domain is active')
     client.connect()
     client.query('select 1', function () {
diff --git a/packages/pg/test/native/evented-api-tests.js b/packages/pg/test/native/evented-api-tests.js
index 5db9e2901..220fcaece 100644
--- a/packages/pg/test/native/evented-api-tests.js
+++ b/packages/pg/test/native/evented-api-tests.js
@@ -1,13 +1,13 @@
 'use strict'
-var helper = require('../test-helper')
-var Client = require('../../lib/native')
-var Query = Client.Query
+const helper = require('../test-helper')
+const Client = require('../../lib/native')
+const Query = Client.Query
 const assert = require('assert')
 const suite = new helper.Suite()
 const test = suite.test.bind(suite)
 
-var setupClient = function () {
-  var client = new Client(helper.config)
+const setupClient = function () {
+  const client = new Client(helper.config)
   client.connect()
   client.query('CREATE TEMP TABLE boom(name varchar(10), age integer)')
   client.query("INSERT INTO boom(name, age) VALUES('Aaron', 26)")
@@ -17,8 +17,8 @@ var setupClient = function () {
 
 test('multiple results', function () {
   test('queued queries', function () {
-    var client = setupClient()
-    var q = client.query(new Query('SELECT name FROM BOOM'))
+    const client = setupClient()
+    const q = client.query(new Query('SELECT name FROM BOOM'))
     assert.emits(q, 'row', function (row) {
       assert.equal(row.name, 'Aaron')
       assert.emits(q, 'row', function (row) {
@@ -27,7 +27,7 @@ test('multiple results', function () {
     })
     assert.emits(q, 'end', function () {
       test('query with config', function () {
-        var q2 = client.query(new Query({ text: 'SELECT 1 as num' }))
+        const q2 = client.query(new Query({ text: 'SELECT 1 as num' }))
         assert.emits(q2, 'row', function (row) {
           assert.strictEqual(row.num, 1)
           assert.emits(q2, 'end', function () {
@@ -41,8 +41,8 @@ test('multiple results', function () {
 
 test('parameterized queries', function () {
   test('with a single string param', function () {
-    var client = setupClient()
-    var q = client.query(new Query('SELECT * FROM boom WHERE name = $1', ['Aaron']))
+    const client = setupClient()
+    const q = client.query(new Query('SELECT * FROM boom WHERE name = $1', ['Aaron']))
     assert.emits(q, 'row', function (row) {
       assert.equal(row.name, 'Aaron')
     })
@@ -52,8 +52,8 @@ test('parameterized queries', function () {
   })
 
   test('with object config for query', function () {
-    var client = setupClient()
-    var q = client.query(
+    const client = setupClient()
+    const q = client.query(
       new Query({
         text: 'SELECT name FROM boom WHERE name = $1',
         values: ['Brian'],
@@ -68,8 +68,8 @@ test('parameterized queries', function () {
   })
 
   test('multiple parameters', function () {
-    var client = setupClient()
-    var q = client.query(
+    const client = setupClient()
+    const q = client.query(
       new Query('SELECT name FROM boom WHERE name = $1 or name = $2 ORDER BY name COLLATE "C"', ['Aaron', 'Brian'])
     )
     assert.emits(q, 'row', function (row) {
@@ -84,8 +84,8 @@ test('parameterized queries', function () {
   })
 
   test('integer parameters', function () {
-    var client = setupClient()
-    var q = client.query(new Query('SELECT * FROM boom WHERE age > $1', [27]))
+    const client = setupClient()
+    const q = client.query(new Query('SELECT * FROM boom WHERE age > $1', [27]))
     assert.emits(q, 'row', function (row) {
       assert.equal(row.name, 'Brian')
       assert.equal(row.age, 28)
diff --git a/packages/pg/test/native/native-connection-string-tests.js b/packages/pg/test/native/native-connection-string-tests.js
index fe814deea..506a45551 100644
--- a/packages/pg/test/native/native-connection-string-tests.js
+++ b/packages/pg/test/native/native-connection-string-tests.js
@@ -1,6 +1,6 @@
 'use strict'
-var helper = require('../test-helper')
-var Client = require('../../lib/native')
+const helper = require('../test-helper')
+const Client = require('../../lib/native')
 const suite = new helper.Suite()
 const assert = require('assert')
 
@@ -11,7 +11,7 @@ suite.test('respects nativeConnectionString in config', function (done) {
   // setting wrong port to make sure config is take from nativeConnectionString and not env
   helper.config.port = '90929'
 
-  var client = new Client({
+  const client = new Client({
     ...helper.config,
     nativeConnectionString,
   })
@@ -35,7 +35,7 @@ suite.test('respects nativeConnectionString in config', function (done) {
 suite.test('respects nativeConnectionString in config even when it is corrupted', function (done) {
   const nativeConnectionString = `foobar`
 
-  var client = new Client({
+  const client = new Client({
     nativeConnectionString,
   })
 
diff --git a/packages/pg/test/native/native-vs-js-error-tests.js b/packages/pg/test/native/native-vs-js-error-tests.js
index 842e01aae..d61b0c69d 100644
--- a/packages/pg/test/native/native-vs-js-error-tests.js
+++ b/packages/pg/test/native/native-vs-js-error-tests.js
@@ -1,10 +1,10 @@
 'use strict'
-var assert = require('assert')
-var Client = require('../../lib/client')
-var NativeClient = require('../../lib/native')
+const assert = require('assert')
+const Client = require('../../lib/client')
+const NativeClient = require('../../lib/native')
 
-var client = new Client()
-var nativeClient = new NativeClient()
+const client = new Client()
+const nativeClient = new NativeClient()
 
 client.connect()
 nativeClient.connect((err) => {
@@ -12,7 +12,7 @@ nativeClient.connect((err) => {
     client.end()
 
     nativeClient.query('SELECT lkdasjfasd', (nativeErr) => {
-      for (var key in nativeErr) {
+      for (const key in nativeErr) {
         assert.equal(err[key], nativeErr[key], `Expected err.${key} to equal nativeErr.${key}`)
       }
       nativeClient.end()
diff --git a/packages/pg/test/native/stress-tests.js b/packages/pg/test/native/stress-tests.js
index 13f03dcdf..2cccb44bf 100644
--- a/packages/pg/test/native/stress-tests.js
+++ b/packages/pg/test/native/stress-tests.js
@@ -1,15 +1,15 @@
 'use strict'
-var helper = require('../test-helper')
-var Client = require('../../lib/native')
-var Query = Client.Query
+const helper = require('../test-helper')
+const Client = require('../../lib/native')
+const Query = Client.Query
 const assert = require('assert')
 const suite = new helper.Suite()
 
 suite.test('many rows', function () {
-  var client = new Client(helper.config)
+  const client = new Client(helper.config)
   client.connect()
-  var q = client.query(new Query('SELECT * FROM person'))
-  var rows = []
+  const q = client.query(new Query('SELECT * FROM person'))
+  const rows = []
   q.on('row', function (row) {
     rows.push(row)
   })
@@ -20,12 +20,12 @@ suite.test('many rows', function () {
 })
 
 suite.test('many queries', function () {
-  var client = new Client(helper.config)
+  const client = new Client(helper.config)
   client.connect()
-  var count = 0
-  var expected = 100
-  for (var i = 0; i < expected; i++) {
-    var q = client.query(new Query('SELECT * FROM person'))
+  let count = 0
+  const expected = 100
+  for (let i = 0; i < expected; i++) {
+    const q = client.query(new Query('SELECT * FROM person'))
     assert.emits(q, 'end', function () {
       count++
     })
@@ -37,13 +37,13 @@ suite.test('many queries', function () {
 })
 
 suite.test('many clients', function () {
-  var clients = []
-  for (var i = 0; i < 10; i++) {
+  const clients = []
+  for (let i = 0; i < 10; i++) {
     clients.push(new Client(helper.config))
   }
   clients.forEach(function (client) {
     client.connect()
-    for (var i = 0; i < 20; i++) {
+    for (let i = 0; i < 20; i++) {
       client.query('SELECT * FROM person')
     }
     assert.emits(client, 'drain', function () {
diff --git a/packages/pg/test/test-buffers.js b/packages/pg/test/test-buffers.js
index 2989434d4..576d22f7e 100644
--- a/packages/pg/test/test-buffers.js
+++ b/packages/pg/test/test-buffers.js
@@ -3,7 +3,7 @@ require('./test-helper')
 const BufferList = require('./buffer-list')
 // http://developer.postgresql.org/pgdocs/postgres/protocol-message-formats.html
 
-var buffers = {}
+const buffers = {}
 buffers.readyForQuery = function () {
   return new BufferList().add(Buffer.from('I')).join(true, 'Z')
 }
@@ -49,7 +49,7 @@ buffers.commandComplete = function (string) {
 
 buffers.rowDescription = function (fields) {
   fields = fields || []
-  var buf = new BufferList()
+  const buf = new BufferList()
   buf.addInt16(fields.length)
   fields.forEach(function (field) {
     buf
@@ -66,13 +66,13 @@ buffers.rowDescription = function (fields) {
 
 buffers.dataRow = function (columns) {
   columns = columns || []
-  var buf = new BufferList()
+  const buf = new BufferList()
   buf.addInt16(columns.length)
   columns.forEach(function (col) {
     if (col == null) {
       buf.addInt32(-1)
     } else {
-      var strBuf = Buffer.from(col, 'utf8')
+      const strBuf = Buffer.from(col, 'utf8')
       buf.addInt32(strBuf.length)
       buf.add(strBuf)
     }
@@ -88,9 +88,9 @@ buffers.notice = function (fields) {
   return errorOrNotice(fields).join(true, 'N')
 }
 
-var errorOrNotice = function (fields) {
+const errorOrNotice = function (fields) {
   fields = fields || []
-  var buf = new BufferList()
+  const buf = new BufferList()
   fields.forEach(function (field) {
     buf.addChar(field.type)
     buf.addCString(field.value)
diff --git a/packages/pg/test/test-helper.js b/packages/pg/test/test-helper.js
index 7a50aac65..a025ab24b 100644
--- a/packages/pg/test/test-helper.js
+++ b/packages/pg/test/test-helper.js
@@ -1,6 +1,6 @@
 'use strict'
 const assert = require('assert')
-var sys = require('util')
+const sys = require('util')
 
 const Suite = require('./suite')
 const args = require('./cli')
@@ -18,14 +18,14 @@ process.on('uncaughtException', function (d) {
 })
 
 assert.same = function (actual, expected) {
-  for (var key in expected) {
+  for (const key in expected) {
     assert.equal(actual[key], expected[key])
   }
 }
 
 assert.emits = function (item, eventName, callback, message) {
-  var called = false
-  var id = setTimeout(function () {
+  let called = false
+  const id = setTimeout(function () {
     test("Should have called '" + eventName + "' event", function () {
       assert.ok(called, message || "Expected '" + eventName + "' to be called.")
     })
@@ -49,25 +49,25 @@ assert.emits = function (item, eventName, callback, message) {
 }
 
 assert.UTCDate = function (actual, year, month, day, hours, min, sec, milisecond) {
-  var actualYear = actual.getUTCFullYear()
+  const actualYear = actual.getUTCFullYear()
   assert.equal(actualYear, year, 'expected year ' + year + ' but got ' + actualYear)
 
-  var actualMonth = actual.getUTCMonth()
+  const actualMonth = actual.getUTCMonth()
   assert.equal(actualMonth, month, 'expected month ' + month + ' but got ' + actualMonth)
 
-  var actualDate = actual.getUTCDate()
+  const actualDate = actual.getUTCDate()
   assert.equal(actualDate, day, 'expected day ' + day + ' but got ' + actualDate)
 
-  var actualHours = actual.getUTCHours()
+  const actualHours = actual.getUTCHours()
   assert.equal(actualHours, hours, 'expected hours ' + hours + ' but got ' + actualHours)
 
-  var actualMin = actual.getUTCMinutes()
+  const actualMin = actual.getUTCMinutes()
   assert.equal(actualMin, min, 'expected min ' + min + ' but got ' + actualMin)
 
-  var actualSec = actual.getUTCSeconds()
+  const actualSec = actual.getUTCSeconds()
   assert.equal(actualSec, sec, 'expected sec ' + sec + ' but got ' + actualSec)
 
-  var actualMili = actual.getUTCMilliseconds()
+  const actualMili = actual.getUTCMilliseconds()
   assert.equal(actualMili, milisecond, 'expected milisecond ' + milisecond + ' but got ' + actualMili)
 }
 
@@ -76,7 +76,7 @@ assert.equalBuffers = function (actual, expected) {
     spit(actual, expected)
     assert.equal(actual.length, expected.length)
   }
-  for (var i = 0; i < actual.length; i++) {
+  for (let i = 0; i < actual.length; i++) {
     if (actual[i] != expected[i]) {
       spit(actual, expected)
     }
@@ -114,10 +114,10 @@ assert.lengthIs = function (actual, expectedLength) {
   assert.equal(actual.length, expectedLength)
 }
 
-var expect = function (callback, timeout) {
-  var executed = false
+const expect = function (callback, timeout) {
+  const executed = false
   timeout = timeout || parseInt(process.env.TEST_TIMEOUT) || 5000
-  var id = setTimeout(function () {
+  const id = setTimeout(function () {
     assert.ok(
       executed,
       'Expected execution of function to be fired within ' +
@@ -171,15 +171,15 @@ process.on('uncaughtException', function (err) {
   process.exit(255)
 })
 
-var getTimezoneOffset = Date.prototype.getTimezoneOffset
+const getTimezoneOffset = Date.prototype.getTimezoneOffset
 
-var setTimezoneOffset = function (minutesOffset) {
+const setTimezoneOffset = function (minutesOffset) {
   Date.prototype.getTimezoneOffset = function () {
     return minutesOffset
   }
 }
 
-var resetTimezoneOffset = function () {
+const resetTimezoneOffset = function () {
   Date.prototype.getTimezoneOffset = getTimezoneOffset
 }
 
diff --git a/packages/pg/test/unit/client/cleartext-password-tests.js b/packages/pg/test/unit/client/cleartext-password-tests.js
index 0cf0b9fe5..388d94cf9 100644
--- a/packages/pg/test/unit/client/cleartext-password-tests.js
+++ b/packages/pg/test/unit/client/cleartext-password-tests.js
@@ -7,19 +7,19 @@ const suite = new helper.Suite()
 const { MemoryStream } = helper
 
 suite.test('cleartext password auth responds with password', function () {
-  var client = createClient()
+  const client = createClient()
   client.password = '!'
   client.connection.stream.packets = []
   client.connection.emit('authenticationCleartextPassword')
-  var packets = client.connection.stream.packets
+  const packets = client.connection.stream.packets
   assert.lengthIs(packets, 1)
-  var packet = packets[0]
+  const packet = packets[0]
   assert.equalBuffers(packet, [0x70, 0, 0, 0, 6, 33, 0])
 })
 
 suite.test('cleartext password auth does not crash with null password using pg-pass', function () {
   process.env.PGPASSFILE = `${__dirname}/pgpass.file`
-  var client = new helper.Client({
+  const client = new helper.Client({
     host: 'foo',
     port: 5432,
     database: 'bar',
diff --git a/packages/pg/test/unit/client/configuration-tests.js b/packages/pg/test/unit/client/configuration-tests.js
index 55e14e143..63d4ea649 100644
--- a/packages/pg/test/unit/client/configuration-tests.js
+++ b/packages/pg/test/unit/client/configuration-tests.js
@@ -1,17 +1,17 @@
 'use strict'
 const helper = require('./test-helper')
 const { Client } = helper
-var assert = require('assert')
+const assert = require('assert')
 const suite = new helper.Suite()
 const test = suite.test.bind(suite)
 
-var pguser = process.env['PGUSER'] || process.env.USER
-var pgdatabase = process.env['PGDATABASE'] || process.env.USER
-var pgport = process.env['PGPORT'] || 5432
+const pguser = process.env['PGUSER'] || process.env.USER
+const pgdatabase = process.env['PGDATABASE'] || process.env.USER
+const pgport = process.env['PGPORT'] || 5432
 
 test('client settings', function () {
   test('defaults', function () {
-    var client = new Client()
+    const client = new Client()
     assert.equal(client.user, pguser)
     assert.equal(client.database, pgdatabase)
     assert.equal(client.port, pgport)
@@ -19,10 +19,10 @@ test('client settings', function () {
   })
 
   test('custom', function () {
-    var user = 'brian'
-    var database = 'pgjstest'
-    var password = 'boom'
-    var client = new Client({
+    const user = 'brian'
+    const database = 'pgjstest'
+    const password = 'boom'
+    const client = new Client({
       user: user,
       database: database,
       port: 321,
@@ -38,20 +38,20 @@ test('client settings', function () {
   })
 
   test('custom ssl default on', function () {
-    var old = process.env.PGSSLMODE
+    const old = process.env.PGSSLMODE
     process.env.PGSSLMODE = 'prefer'
 
-    var client = new Client()
+    const client = new Client()
     process.env.PGSSLMODE = old
 
     assert.equal(client.ssl, true)
   })
 
   test('custom ssl force off', function () {
-    var old = process.env.PGSSLMODE
+    const old = process.env.PGSSLMODE
     process.env.PGSSLMODE = 'prefer'
 
-    var client = new Client({
+    const client = new Client({
       ssl: false,
     })
     process.env.PGSSLMODE = old
@@ -62,7 +62,7 @@ test('client settings', function () {
 
 test('initializing from a config string', function () {
   test('uses connectionString property', function () {
-    var client = new Client({
+    const client = new Client({
       connectionString: 'postgres://brian:pass@host1:333/databasename',
     })
     assert.equal(client.user, 'brian')
@@ -73,7 +73,7 @@ test('initializing from a config string', function () {
   })
 
   test('uses the correct values from the config string', function () {
-    var client = new Client('postgres://brian:pass@host1:333/databasename')
+    const client = new Client('postgres://brian:pass@host1:333/databasename')
     assert.equal(client.user, 'brian')
     assert.equal(client.password, 'pass')
     assert.equal(client.host, 'host1')
@@ -82,7 +82,7 @@ test('initializing from a config string', function () {
   })
 
   test('uses the correct values from the config string with space in password', function () {
-    var client = new Client('postgres://brian:pass word@host1:333/databasename')
+    const client = new Client('postgres://brian:pass word@host1:333/databasename')
     assert.equal(client.user, 'brian')
     assert.equal(client.password, 'pass word')
     assert.equal(client.host, 'host1')
@@ -91,7 +91,7 @@ test('initializing from a config string', function () {
   })
 
   test('when not including all values the defaults are used', function () {
-    var client = new Client('postgres://host1')
+    const client = new Client('postgres://host1')
     assert.equal(client.user, process.env['PGUSER'] || process.env.USER)
     assert.equal(client.password, process.env['PGPASSWORD'] || null)
     assert.equal(client.host, 'host1')
@@ -100,17 +100,17 @@ test('initializing from a config string', function () {
   })
 
   test('when not including all values the environment variables are used', function () {
-    var envUserDefined = process.env['PGUSER'] !== undefined
-    var envPasswordDefined = process.env['PGPASSWORD'] !== undefined
-    var envHostDefined = process.env['PGHOST'] !== undefined
-    var envPortDefined = process.env['PGPORT'] !== undefined
-    var envDBDefined = process.env['PGDATABASE'] !== undefined
-
-    var savedEnvUser = process.env['PGUSER']
-    var savedEnvPassword = process.env['PGPASSWORD']
-    var savedEnvHost = process.env['PGHOST']
-    var savedEnvPort = process.env['PGPORT']
-    var savedEnvDB = process.env['PGDATABASE']
+    const envUserDefined = process.env['PGUSER'] !== undefined
+    const envPasswordDefined = process.env['PGPASSWORD'] !== undefined
+    const envHostDefined = process.env['PGHOST'] !== undefined
+    const envPortDefined = process.env['PGPORT'] !== undefined
+    const envDBDefined = process.env['PGDATABASE'] !== undefined
+
+    const savedEnvUser = process.env['PGUSER']
+    const savedEnvPassword = process.env['PGPASSWORD']
+    const savedEnvHost = process.env['PGHOST']
+    const savedEnvPort = process.env['PGPORT']
+    const savedEnvDB = process.env['PGDATABASE']
 
     process.env['PGUSER'] = 'utUser1'
     process.env['PGPASSWORD'] = 'utPass1'
@@ -118,7 +118,7 @@ test('initializing from a config string', function () {
     process.env['PGPORT'] = 5464
     process.env['PGDATABASE'] = 'utDB1'
 
-    var client = new Client('postgres://host1')
+    const client = new Client('postgres://host1')
     assert.equal(client.user, process.env['PGUSER'])
     assert.equal(client.password, process.env['PGPASSWORD'])
     assert.equal(client.host, 'host1')
@@ -158,9 +158,9 @@ test('initializing from a config string', function () {
 })
 
 test('calls connect correctly on connection', function () {
-  var client = new Client('/tmp')
-  var usedPort = ''
-  var usedHost = ''
+  const client = new Client('/tmp')
+  let usedPort = ''
+  let usedHost = ''
   client.connection.connect = function (port, host) {
     usedPort = port
     usedHost = host
diff --git a/packages/pg/test/unit/client/early-disconnect-tests.js b/packages/pg/test/unit/client/early-disconnect-tests.js
index 5e8880c7e..f62ce62d1 100644
--- a/packages/pg/test/unit/client/early-disconnect-tests.js
+++ b/packages/pg/test/unit/client/early-disconnect-tests.js
@@ -1,17 +1,17 @@
 'use strict'
 require('./test-helper')
-var net = require('net')
-var pg = require('../../../lib/index.js')
+const net = require('net')
+const pg = require('../../../lib/index.js')
 const assert = require('assert')
 
 /* console.log() messages show up in `make test` output. TODO: fix it. */
-var server = net.createServer(function (c) {
+const server = net.createServer(function (c) {
   c.destroy()
   server.close()
 })
 
 server.listen(7777, function () {
-  var client = new pg.Client('postgres://localhost:7777')
+  const client = new pg.Client('postgres://localhost:7777')
   client.connect(
     assert.calls(function (err) {
       assert(err)
diff --git a/packages/pg/test/unit/client/escape-tests.js b/packages/pg/test/unit/client/escape-tests.js
index 2b5f64499..e19ef14be 100644
--- a/packages/pg/test/unit/client/escape-tests.js
+++ b/packages/pg/test/unit/client/escape-tests.js
@@ -1,43 +1,43 @@
 'use strict'
-var helper = require('./test-helper')
-var utils = require('../../../lib/utils')
+const helper = require('./test-helper')
+const utils = require('../../../lib/utils')
 const assert = require('assert')
 const { Client, Suite } = helper
 const suite = new Suite()
 const test = suite.test.bind(suite)
 
-var testLit = function (testName, input, expected) {
+const testLit = function (testName, input, expected) {
   test(testName, function () {
-    var client = new Client(helper.config)
-    var actual = client.escapeLiteral(input)
+    const client = new Client(helper.config)
+    const actual = client.escapeLiteral(input)
     assert.equal(expected, actual)
   })
 
   test('Client.prototype.' + testName, function () {
-    var actual = Client.prototype.escapeLiteral(input)
+    const actual = Client.prototype.escapeLiteral(input)
     assert.equal(expected, actual)
   })
 
   test('utils.' + testName, function () {
-    var actual = utils.escapeLiteral(input)
+    const actual = utils.escapeLiteral(input)
     assert.equal(expected, actual)
   })
 }
 
-var testIdent = function (testName, input, expected) {
+const testIdent = function (testName, input, expected) {
   test(testName, function () {
-    var client = new Client(helper.config)
-    var actual = client.escapeIdentifier(input)
+    const client = new Client(helper.config)
+    const actual = client.escapeIdentifier(input)
     assert.equal(expected, actual)
   })
 
   test('Client.prototype.' + testName, function () {
-    var actual = Client.prototype.escapeIdentifier(input)
+    const actual = Client.prototype.escapeIdentifier(input)
     assert.equal(expected, actual)
   })
 
   test('utils.' + testName, function () {
-    var actual = utils.escapeIdentifier(input)
+    const actual = utils.escapeIdentifier(input)
     assert.equal(expected, actual)
   })
 }
diff --git a/packages/pg/test/unit/client/md5-password-tests.js b/packages/pg/test/unit/client/md5-password-tests.js
index e4cb9b3e6..8fd2f7c2f 100644
--- a/packages/pg/test/unit/client/md5-password-tests.js
+++ b/packages/pg/test/unit/client/md5-password-tests.js
@@ -1,22 +1,22 @@
 'use strict'
-var helper = require('./test-helper')
+const helper = require('./test-helper')
 const BufferList = require('../../buffer-list')
-var crypto = require('../../../lib/crypto/utils')
+const crypto = require('../../../lib/crypto/utils')
 const assert = require('assert')
 const suite = new helper.Suite()
 const test = suite.test.bind(suite)
 
 test('md5 authentication', async function () {
-  var client = helper.createClient()
+  const client = helper.createClient()
   client.password = '!'
-  var salt = Buffer.from([1, 2, 3, 4])
+  const salt = Buffer.from([1, 2, 3, 4])
   await client.connection.emit('authenticationMD5Password', { salt: salt })
 
   setTimeout(() =>
     test('responds', function () {
       assert.lengthIs(client.connection.stream.packets, 1)
       test('should have correct encrypted data', async function () {
-        var password = await crypto.postgresMd5PasswordHash(client.user, client.password, salt)
+        const password = await crypto.postgresMd5PasswordHash(client.user, client.password, salt)
         // how do we want to test this?
         assert.equalBuffers(client.connection.stream.packets[0], new BufferList().addCString(password).join(true, 'p'))
       })
diff --git a/packages/pg/test/unit/client/notification-tests.js b/packages/pg/test/unit/client/notification-tests.js
index 25d0e9f48..55efdbad8 100644
--- a/packages/pg/test/unit/client/notification-tests.js
+++ b/packages/pg/test/unit/client/notification-tests.js
@@ -1,10 +1,10 @@
 'use strict'
-var helper = require('./test-helper')
+const helper = require('./test-helper')
 const assert = require('assert')
 const suite = new helper.Suite()
 
 suite.test('passes connection notification', function () {
-  var client = helper.client()
+  const client = helper.client()
   assert.emits(client, 'notice', function (msg) {
     assert.equal(msg, 'HAY!!')
   })
diff --git a/packages/pg/test/unit/client/prepared-statement-tests.js b/packages/pg/test/unit/client/prepared-statement-tests.js
index ba080dd59..71f9d094b 100644
--- a/packages/pg/test/unit/client/prepared-statement-tests.js
+++ b/packages/pg/test/unit/client/prepared-statement-tests.js
@@ -1,13 +1,13 @@
 'use strict'
-var helper = require('./test-helper')
-var Query = require('../../../lib/query')
+const helper = require('./test-helper')
+const Query = require('../../../lib/query')
 const assert = require('assert')
-var client = helper.client()
+const client = helper.client()
 const suite = new helper.Suite()
 const test = suite.test.bind(suite)
 
-var con = client.connection
-var parseArg = null
+const con = client.connection
+let parseArg = null
 con.parse = function (arg) {
   parseArg = arg
   process.nextTick(function () {
@@ -15,7 +15,7 @@ con.parse = function (arg) {
   })
 }
 
-var bindArg = null
+let bindArg = null
 con.bind = function (arg) {
   bindArg = arg
   process.nextTick(function () {
@@ -23,7 +23,7 @@ con.bind = function (arg) {
   })
 }
 
-var executeArg = null
+let executeArg = null
 con.execute = function (arg) {
   executeArg = arg
   process.nextTick(function () {
@@ -32,7 +32,7 @@ con.execute = function (arg) {
   })
 }
 
-var describeArg = null
+let describeArg = null
 con.describe = function (arg) {
   describeArg = arg
   process.nextTick(function () {
@@ -40,7 +40,7 @@ con.describe = function (arg) {
   })
 }
 
-var syncCalled = false
+let syncCalled = false
 con.flush = function () {}
 con.sync = function () {
   syncCalled = true
@@ -53,7 +53,7 @@ test('bound command', function () {
   test('simple, unnamed bound command', function () {
     assert.ok(client.connection.emit('readyForQuery'))
 
-    var query = client.query(
+    const query = client.query(
       new Query({
         text: 'select * from X where name = $1',
         values: ['hi'],
@@ -91,15 +91,15 @@ test('bound command', function () {
   })
 })
 
-var portalClient = helper.client()
-var portalCon = portalClient.connection
+const portalClient = helper.client()
+const portalCon = portalClient.connection
 portalCon.parse = function (arg) {
   process.nextTick(function () {
     portalCon.emit('parseComplete')
   })
 }
 
-var portalBindArg = null
+let portalBindArg = null
 portalCon.bind = function (arg) {
   portalBindArg = arg
   process.nextTick(function () {
@@ -107,7 +107,7 @@ portalCon.bind = function (arg) {
   })
 }
 
-var portalExecuteArg = null
+let portalExecuteArg = null
 portalCon.execute = function (arg) {
   portalExecuteArg = arg
   process.nextTick(function () {
@@ -116,7 +116,7 @@ portalCon.execute = function (arg) {
   })
 }
 
-var portalDescribeArg = null
+let portalDescribeArg = null
 portalCon.describe = function (arg) {
   portalDescribeArg = arg
   process.nextTick(function () {
@@ -134,7 +134,7 @@ portalCon.sync = function () {
 test('prepared statement with explicit portal', function () {
   assert.ok(portalClient.connection.emit('readyForQuery'))
 
-  var query = portalClient.query(
+  const query = portalClient.query(
     new Query({
       text: 'select * from X where name = $1',
       portal: 'myportal',
diff --git a/packages/pg/test/unit/client/query-queue-tests.js b/packages/pg/test/unit/client/query-queue-tests.js
index ede3293fc..1566afc43 100644
--- a/packages/pg/test/unit/client/query-queue-tests.js
+++ b/packages/pg/test/unit/client/query-queue-tests.js
@@ -1,21 +1,21 @@
 'use strict'
 const helper = require('./test-helper')
 const { Client } = helper
-var Connection = require('../../../lib/connection')
+const Connection = require('../../../lib/connection')
 const assert = require('assert')
 const suite = new helper.Suite()
 const test = suite.test.bind(suite)
 
 test('drain', function () {
-  var con = new Connection({ stream: 'NO' })
-  var client = new Client({ connection: con })
+  const con = new Connection({ stream: 'NO' })
+  const client = new Client({ connection: con })
   con.connect = function () {
     con.emit('connect')
   }
   con.query = function () {}
   client.connect()
 
-  var raisedDrain = false
+  let raisedDrain = false
   client.on('drain', function () {
     raisedDrain = true
   })
diff --git a/packages/pg/test/unit/client/result-metadata-tests.js b/packages/pg/test/unit/client/result-metadata-tests.js
index e37209872..bbc85c7af 100644
--- a/packages/pg/test/unit/client/result-metadata-tests.js
+++ b/packages/pg/test/unit/client/result-metadata-tests.js
@@ -1,12 +1,12 @@
 'use strict'
-var helper = require('./test-helper')
+const helper = require('./test-helper')
 const assert = require('assert')
 const suite = new helper.Suite()
 const test = suite.test.bind(suite)
 
-var testForTag = function (tagText, callback) {
+const testForTag = function (tagText, callback) {
   test('includes command tag data for tag ' + tagText, function () {
-    var client = helper.client()
+    const client = helper.client()
     client.connection.emit('readyForQuery')
 
     client.query(
@@ -26,7 +26,7 @@ var testForTag = function (tagText, callback) {
   })
 }
 
-var check = function (oid, rowCount, command) {
+const check = function (oid, rowCount, command) {
   return function (result) {
     if (oid != null) {
       assert.equal(result.oid, oid)
diff --git a/packages/pg/test/unit/client/sasl-scram-tests.js b/packages/pg/test/unit/client/sasl-scram-tests.js
index 2e1ed6a2f..fca48efb2 100644
--- a/packages/pg/test/unit/client/sasl-scram-tests.js
+++ b/packages/pg/test/unit/client/sasl-scram-tests.js
@@ -2,7 +2,7 @@
 const helper = require('./test-helper')
 const assert = require('assert')
 
-var sasl = require('../../../lib/crypto/sasl')
+const sasl = require('../../../lib/crypto/sasl')
 
 const suite = new helper.Suite()
 
diff --git a/packages/pg/test/unit/client/simple-query-tests.js b/packages/pg/test/unit/client/simple-query-tests.js
index 3fecc1435..f82c3e661 100644
--- a/packages/pg/test/unit/client/simple-query-tests.js
+++ b/packages/pg/test/unit/client/simple-query-tests.js
@@ -1,6 +1,6 @@
 'use strict'
-var helper = require('./test-helper')
-var Query = require('../../../lib/query')
+const helper = require('./test-helper')
+const Query = require('../../../lib/query')
 const assert = require('assert')
 const suite = new helper.Suite()
 const test = suite.test.bind(suite)
@@ -8,7 +8,7 @@ const test = suite.test.bind(suite)
 test('executing query', function () {
   test('queing query', function () {
     test('when connection is ready', function () {
-      var client = helper.client()
+      const client = helper.client()
       assert.empty(client.connection.queries)
       client.connection.emit('readyForQuery')
       client.query('yes')
@@ -17,7 +17,7 @@ test('executing query', function () {
     })
 
     test('when connection is not ready', function () {
-      var client = helper.client()
+      const client = helper.client()
 
       test('query is not sent', function () {
         client.query('boom')
@@ -32,9 +32,9 @@ test('executing query', function () {
     })
 
     test('multiple in the queue', function () {
-      var client = helper.client()
-      var connection = client.connection
-      var queries = connection.queries
+      const client = helper.client()
+      const connection = client.connection
+      const queries = connection.queries
       client.query('one')
       client.query('two')
       client.query('three')
@@ -64,9 +64,9 @@ test('executing query', function () {
   })
 
   test('query event binding and flow', function () {
-    var client = helper.client()
-    var con = client.connection
-    var query = client.query(new Query('whatever'))
+    const client = helper.client()
+    const con = client.connection
+    const query = client.query(new Query('whatever'))
 
     test('has no queries sent before ready', function () {
       assert.empty(con.queries)
@@ -79,7 +79,7 @@ test('executing query', function () {
     })
 
     test('handles rowDescription message', function () {
-      var handled = con.emit('rowDescription', {
+      const handled = con.emit('rowDescription', {
         fields: [
           {
             name: 'boom',
@@ -94,14 +94,14 @@ test('executing query', function () {
         assert.equal(row['boom'], 'hi')
       })
 
-      var handled = con.emit('dataRow', { fields: ['hi'] })
+      const handled = con.emit('dataRow', { fields: ['hi'] })
       assert.ok(handled, 'should have handled first data row message')
 
       assert.emits(query, 'row', function (row) {
         assert.equal(row['boom'], 'bye')
       })
 
-      var handledAgain = con.emit('dataRow', { fields: ['bye'] })
+      const handledAgain = con.emit('dataRow', { fields: ['bye'] })
       assert.ok(handledAgain, 'should have handled seciond data row message')
     })
 
@@ -119,7 +119,7 @@ test('executing query', function () {
   })
 
   test('handles errors', function () {
-    var client = helper.client()
+    const client = helper.client()
 
     test('throws an error when config is null', function () {
       try {
diff --git a/packages/pg/test/unit/client/stream-and-query-error-interaction-tests.js b/packages/pg/test/unit/client/stream-and-query-error-interaction-tests.js
index 6f0da6142..8a5e4656c 100644
--- a/packages/pg/test/unit/client/stream-and-query-error-interaction-tests.js
+++ b/packages/pg/test/unit/client/stream-and-query-error-interaction-tests.js
@@ -1,12 +1,12 @@
 'use strict'
 const helper = require('./test-helper')
-var Connection = require('../../../lib/connection')
-var Client = require('../../../lib/client')
+const Connection = require('../../../lib/connection')
+const Client = require('../../../lib/client')
 const assert = require('assert')
 const suite = new helper.Suite()
 
 suite.test('emits end when not in query', function () {
-  var stream = new (require('events').EventEmitter)()
+  const stream = new (require('events').EventEmitter)()
   stream.setNoDelay = () => {}
   stream.connect = function () {
     // NOOP
@@ -15,7 +15,7 @@ suite.test('emits end when not in query', function () {
     // NOOP
   }
 
-  var client = new Client({ connection: new Connection({ stream: stream }) })
+  const client = new Client({ connection: new Connection({ stream: stream }) })
   client.connect(
     assert.calls(function () {
       client.query(
diff --git a/packages/pg/test/unit/client/test-helper.js b/packages/pg/test/unit/client/test-helper.js
index 1a89a59f5..3e8f75c31 100644
--- a/packages/pg/test/unit/client/test-helper.js
+++ b/packages/pg/test/unit/client/test-helper.js
@@ -1,17 +1,17 @@
 'use strict'
-var helper = require('../test-helper')
-var Connection = require('../../../lib/connection')
+const helper = require('../test-helper')
+const Connection = require('../../../lib/connection')
 const { Client } = helper
 
-var makeClient = function () {
-  var connection = new Connection({ stream: 'no' })
+const makeClient = function () {
+  const connection = new Connection({ stream: 'no' })
   connection.startup = function () {}
   connection.connect = function () {}
   connection.query = function (text) {
     this.queries.push(text)
   }
   connection.queries = []
-  var client = new Client({ connection: connection })
+  const client = new Client({ connection: connection })
   client.connect()
   client.connection.emit('connect')
   return client
diff --git a/packages/pg/test/unit/client/throw-in-type-parser-tests.js b/packages/pg/test/unit/client/throw-in-type-parser-tests.js
index cf1a35364..2428a121b 100644
--- a/packages/pg/test/unit/client/throw-in-type-parser-tests.js
+++ b/packages/pg/test/unit/client/throw-in-type-parser-tests.js
@@ -1,12 +1,12 @@
 'use strict'
-var helper = require('./test-helper')
-var Query = require('../../../lib/query')
-var types = require('pg-types')
+const helper = require('./test-helper')
+const Query = require('../../../lib/query')
+const types = require('pg-types')
 const assert = require('assert')
 
 const suite = new helper.Suite()
 
-var typeParserError = new Error('TEST: Throw in type parsers')
+const typeParserError = new Error('TEST: Throw in type parsers')
 
 types.setTypeParser('special oid that will throw', function () {
   throw typeParserError
@@ -33,9 +33,9 @@ const emitFakeEvents = (con) => {
 }
 
 suite.test('emits error', function (done) {
-  var client = helper.client()
-  var con = client.connection
-  var query = client.query(new Query('whatever'))
+  const client = helper.client()
+  const con = client.connection
+  const query = client.query(new Query('whatever'))
   emitFakeEvents(con)
 
   assert.emits(query, 'error', function (err) {
@@ -45,8 +45,8 @@ suite.test('emits error', function (done) {
 })
 
 suite.test('calls callback with error', function (done) {
-  var client = helper.client()
-  var con = client.connection
+  const client = helper.client()
+  const con = client.connection
   emitFakeEvents(con)
   client.query('whatever', function (err) {
     assert.equal(err, typeParserError)
@@ -55,8 +55,8 @@ suite.test('calls callback with error', function (done) {
 })
 
 suite.test('rejects promise with error', function (done) {
-  var client = helper.client()
-  var con = client.connection
+  const client = helper.client()
+  const con = client.connection
   emitFakeEvents(con)
   client.query('whatever').catch((err) => {
     assert.equal(err, typeParserError)
diff --git a/packages/pg/test/unit/connection-parameters/creation-tests.js b/packages/pg/test/unit/connection-parameters/creation-tests.js
index 5225b9773..158f1dbeb 100644
--- a/packages/pg/test/unit/connection-parameters/creation-tests.js
+++ b/packages/pg/test/unit/connection-parameters/creation-tests.js
@@ -6,7 +6,7 @@ const defaults = require('../../../lib').defaults
 const dns = require('dns')
 
 // clear process.env
-for (var key in process.env) {
+for (const key in process.env) {
   delete process.env[key]
 }
 
@@ -18,7 +18,7 @@ suite.test('ConnectionParameters construction', function () {
   assert.ok(new ConnectionParameters('postgres://localhost/postgres'), 'with connection string')
 })
 
-var compare = function (actual, expected, type) {
+const compare = function (actual, expected, type) {
   const expectedDatabase = expected.database === undefined ? expected.user : expected.database
 
   assert.equal(actual.user, expected.user, type + ' user')
@@ -38,13 +38,13 @@ var compare = function (actual, expected, type) {
 }
 
 suite.test('ConnectionParameters initializing from defaults', function () {
-  var subject = new ConnectionParameters()
+  const subject = new ConnectionParameters()
   compare(subject, defaults, 'defaults')
   assert.ok(subject.isDomainSocket === false)
 })
 
 suite.test('ConnectionParameters initializing from defaults with connectionString set', function () {
-  var config = {
+  const config = {
     user: 'brians-are-the-best',
     database: 'scoobysnacks',
     port: 7777,
@@ -57,18 +57,18 @@ suite.test('ConnectionParameters initializing from defaults with connectionStrin
     options: '-c geqo=off',
   }
 
-  var original_value = defaults.connectionString
+  const original_value = defaults.connectionString
   // Just changing this here doesn't actually work because it's no longer in scope when viewed inside of
   // of ConnectionParameters() so we have to pass in the defaults explicitly to test it
   defaults.connectionString =
     'postgres://brians-are-the-best:mypassword@foo.bar.net:7777/scoobysnacks?options=-c geqo=off'
-  var subject = new ConnectionParameters(defaults)
+  const subject = new ConnectionParameters(defaults)
   defaults.connectionString = original_value
   compare(subject, config, 'defaults-connectionString')
 })
 
 suite.test('ConnectionParameters initializing from config', function () {
-  var config = {
+  const config = {
     user: 'brian',
     database: 'home',
     port: 7777,
@@ -84,23 +84,23 @@ suite.test('ConnectionParameters initializing from config', function () {
     idle_in_transaction_session_timeout: 15000,
     options: '-c geqo=off',
   }
-  var subject = new ConnectionParameters(config)
+  const subject = new ConnectionParameters(config)
   compare(subject, config, 'config')
   assert.ok(subject.isDomainSocket === false)
 })
 
 suite.test('ConnectionParameters initializing from config and config.connectionString', function () {
-  var subject1 = new ConnectionParameters({
+  const subject1 = new ConnectionParameters({
     connectionString: 'postgres://test@host/db',
   })
-  var subject2 = new ConnectionParameters({
+  const subject2 = new ConnectionParameters({
     connectionString: 'postgres://test@host/db?ssl=1',
   })
-  var subject3 = new ConnectionParameters({
+  const subject3 = new ConnectionParameters({
     connectionString: 'postgres://test@host/db',
     ssl: true,
   })
-  var subject4 = new ConnectionParameters({
+  const subject4 = new ConnectionParameters({
     connectionString: 'postgres://test@host/db?ssl=1',
     ssl: false,
   })
@@ -112,31 +112,31 @@ suite.test('ConnectionParameters initializing from config and config.connectionS
 })
 
 suite.test('escape spaces if present', function () {
-  var subject = new ConnectionParameters('postgres://localhost/post gres')
+  const subject = new ConnectionParameters('postgres://localhost/post gres')
   assert.equal(subject.database, 'post gres')
 })
 
 suite.test('do not double escape spaces', function () {
-  var subject = new ConnectionParameters('postgres://localhost/post%20gres')
+  const subject = new ConnectionParameters('postgres://localhost/post%20gres')
   assert.equal(subject.database, 'post gres')
 })
 
 suite.test('initializing with unix domain socket', function () {
-  var subject = new ConnectionParameters('/var/run/')
+  const subject = new ConnectionParameters('/var/run/')
   assert.ok(subject.isDomainSocket)
   assert.equal(subject.host, '/var/run/')
   assert.equal(subject.database, defaults.user)
 })
 
 suite.test('initializing with unix domain socket and a specific database, the simple way', function () {
-  var subject = new ConnectionParameters('/var/run/ mydb')
+  const subject = new ConnectionParameters('/var/run/ mydb')
   assert.ok(subject.isDomainSocket)
   assert.equal(subject.host, '/var/run/')
   assert.equal(subject.database, 'mydb')
 })
 
 suite.test('initializing with unix domain socket, the health way', function () {
-  var subject = new ConnectionParameters('socket:/some path/?db=my[db]&encoding=utf8')
+  const subject = new ConnectionParameters('socket:/some path/?db=my[db]&encoding=utf8')
   assert.ok(subject.isDomainSocket)
   assert.equal(subject.host, '/some path/')
   assert.equal(subject.database, 'my[db]', 'must to be escaped and unescaped trough "my%5Bdb%5D"')
@@ -144,14 +144,14 @@ suite.test('initializing with unix domain socket, the health way', function () {
 })
 
 suite.test('initializing with unix domain socket, the escaped health way', function () {
-  var subject = new ConnectionParameters('socket:/some%20path/?db=my%2Bdb&encoding=utf8')
+  const subject = new ConnectionParameters('socket:/some%20path/?db=my%2Bdb&encoding=utf8')
   assert.ok(subject.isDomainSocket)
   assert.equal(subject.host, '/some path/')
   assert.equal(subject.database, 'my+db')
   assert.equal(subject.client_encoding, 'utf8')
 })
 
-var checkForPart = function (array, part) {
+const checkForPart = function (array, part) {
   assert.ok(array.indexOf(part) > -1, array.join(' ') + ' did not contain ' + part)
 }
 
@@ -164,19 +164,19 @@ const getDNSHost = async function (host) {
 }
 
 suite.testAsync('builds simple string', async function () {
-  var config = {
+  const config = {
     user: 'brian',
     password: 'xyz',
     host: 'localhost',
     port: 888,
     database: 'bam',
   }
-  var subject = new ConnectionParameters(config)
+  const subject = new ConnectionParameters(config)
   const dnsHost = await getDNSHost(config.host)
   return new Promise((resolve) => {
     subject.getLibpqConnectionString(function (err, constring) {
       assert(!err)
-      var parts = constring.split(' ')
+      const parts = constring.split(' ')
       checkForPart(parts, "user='brian'")
       checkForPart(parts, "password='xyz'")
       checkForPart(parts, `hostaddr='${dnsHost}'`)
@@ -188,18 +188,18 @@ suite.testAsync('builds simple string', async function () {
 })
 
 suite.test('builds dns string', async function () {
-  var config = {
+  const config = {
     user: 'brian',
     password: 'asdf',
     host: 'localhost',
     port: 5432,
   }
-  var subject = new ConnectionParameters(config)
+  const subject = new ConnectionParameters(config)
   const dnsHost = await getDNSHost(config.host)
   return new Promise((resolve) => {
     subject.getLibpqConnectionString(function (err, constring) {
       assert(!err)
-      var parts = constring.split(' ')
+      const parts = constring.split(' ')
       checkForPart(parts, "user='brian'")
       checkForPart(parts, `hostaddr='${dnsHost}'`)
       resolve()
@@ -208,13 +208,13 @@ suite.test('builds dns string', async function () {
 })
 
 suite.test('error when dns fails', function () {
-  var config = {
+  const config = {
     user: 'brian',
     password: 'asf',
     host: 'asdlfkjasldfkksfd#!$!!!!..com',
     port: 5432,
   }
-  var subject = new ConnectionParameters(config)
+  const subject = new ConnectionParameters(config)
   subject.getLibpqConnectionString(
     assert.calls(function (err, constring) {
       assert.ok(err)
@@ -224,17 +224,17 @@ suite.test('error when dns fails', function () {
 })
 
 suite.test('connecting to unix domain socket', function () {
-  var config = {
+  const config = {
     user: 'brian',
     password: 'asf',
     host: '/tmp/',
     port: 5432,
   }
-  var subject = new ConnectionParameters(config)
+  const subject = new ConnectionParameters(config)
   subject.getLibpqConnectionString(
     assert.calls(function (err, constring) {
       assert(!err)
-      var parts = constring.split(' ')
+      const parts = constring.split(' ')
       checkForPart(parts, "user='brian'")
       checkForPart(parts, "host='/tmp/'")
     })
@@ -242,17 +242,17 @@ suite.test('connecting to unix domain socket', function () {
 })
 
 suite.test('config contains quotes and backslashes', function () {
-  var config = {
+  const config = {
     user: 'not\\brian',
     password: "bad'chars",
     host: '/tmp/',
     port: 5432,
   }
-  var subject = new ConnectionParameters(config)
+  const subject = new ConnectionParameters(config)
   subject.getLibpqConnectionString(
     assert.calls(function (err, constring) {
       assert(!err)
-      var parts = constring.split(' ')
+      const parts = constring.split(' ')
       checkForPart(parts, "user='not\\\\brian'")
       checkForPart(parts, "password='bad\\'chars'")
     })
@@ -260,28 +260,28 @@ suite.test('config contains quotes and backslashes', function () {
 })
 
 suite.test('encoding can be specified by config', function () {
-  var config = {
+  const config = {
     client_encoding: 'utf-8',
   }
-  var subject = new ConnectionParameters(config)
+  const subject = new ConnectionParameters(config)
   subject.getLibpqConnectionString(
     assert.calls(function (err, constring) {
       assert(!err)
-      var parts = constring.split(' ')
+      const parts = constring.split(' ')
       checkForPart(parts, "client_encoding='utf-8'")
     })
   )
 })
 
 suite.test('password contains  < and/or >  characters', function () {
-  var sourceConfig = {
+  const sourceConfig = {
     user: 'brian',
     password: 'hello<ther>e',
     host: 'localhost',
     port: 5432,
     database: 'postgres',
   }
-  var connectionString =
+  const connectionString =
     'postgres://' +
     sourceConfig.user +
     ':' +
@@ -292,15 +292,15 @@ suite.test('password contains  < and/or >  characters', function () {
     sourceConfig.port +
     '/' +
     sourceConfig.database
-  var subject = new ConnectionParameters(connectionString)
+  const subject = new ConnectionParameters(connectionString)
   assert.equal(subject.password, sourceConfig.password)
 })
 
 suite.test('username or password contains weird characters', function () {
-  var defaults = require('../../../lib/defaults')
+  const defaults = require('../../../lib/defaults')
   defaults.ssl = true
-  var strang = 'pg://my f%irst name:is&%awesome!@localhost:9000'
-  var subject = new ConnectionParameters(strang)
+  const strang = 'pg://my f%irst name:is&%awesome!@localhost:9000'
+  const subject = new ConnectionParameters(strang)
   assert.equal(subject.user, 'my f%irst name')
   assert.equal(subject.password, 'is&%awesome!')
   assert.equal(subject.host, 'localhost')
@@ -308,8 +308,8 @@ suite.test('username or password contains weird characters', function () {
 })
 
 suite.test('url is properly encoded', function () {
-  var encoded = 'pg://bi%25na%25%25ry%20:s%40f%23@localhost/%20u%2520rl'
-  var subject = new ConnectionParameters(encoded)
+  const encoded = 'pg://bi%25na%25%25ry%20:s%40f%23@localhost/%20u%2520rl'
+  const subject = new ConnectionParameters(encoded)
   assert.equal(subject.user, 'bi%na%%ry ')
   assert.equal(subject.password, 's@f#')
   assert.equal(subject.host, 'localhost')
@@ -317,10 +317,10 @@ suite.test('url is properly encoded', function () {
 })
 
 suite.test('ssl is set on client', function () {
-  var Client = require('../../../lib/client')
-  var defaults = require('../../../lib/defaults')
+  const Client = require('../../../lib/client')
+  const defaults = require('../../../lib/defaults')
   defaults.ssl = true
-  var c = new Client('postgres://user:password@host/database')
+  const c = new Client('postgres://user:password@host/database')
   assert(c.ssl, 'Client should have ssl enabled via defaults')
 })
 
@@ -330,7 +330,7 @@ suite.test('coercing string "true" to boolean', function () {
 })
 
 suite.test('ssl is set on client', function () {
-  var sourceConfig = {
+  const sourceConfig = {
     user: 'brian',
     password: 'hello<ther>e',
     host: 'localhost',
@@ -344,9 +344,9 @@ suite.test('ssl is set on client', function () {
       sslrootcert: '/path/root.crt',
     },
   }
-  var defaults = require('../../../lib/defaults')
+  const defaults = require('../../../lib/defaults')
   defaults.ssl = true
-  var c = new ConnectionParameters(sourceConfig)
+  const c = new ConnectionParameters(sourceConfig)
   c.getLibpqConnectionString(
     assert.calls(function (err, pgCString) {
       assert(!err)
diff --git a/packages/pg/test/unit/connection-parameters/environment-variable-tests.js b/packages/pg/test/unit/connection-parameters/environment-variable-tests.js
index e4e08ebd5..068814365 100644
--- a/packages/pg/test/unit/connection-parameters/environment-variable-tests.js
+++ b/packages/pg/test/unit/connection-parameters/environment-variable-tests.js
@@ -1,13 +1,13 @@
 'use strict'
 const Suite = require('../../suite')
 
-var assert = require('assert')
-var ConnectionParameters = require('../../../lib/connection-parameters')
-var defaults = require('../../../lib').defaults
+const assert = require('assert')
+const ConnectionParameters = require('../../../lib/connection-parameters')
+const defaults = require('../../../lib').defaults
 
 // clear process.env
-var realEnv = {}
-for (var key in process.env) {
+const realEnv = {}
+for (const key in process.env) {
   realEnv[key] = process.env[key]
   delete process.env[key]
 }
@@ -16,7 +16,7 @@ const suite = new Suite('ConnectionParameters')
 
 const clearEnv = () => {
   // clear process.env
-  for (var key in process.env) {
+  for (const key in process.env) {
     delete process.env[key]
   }
 }
@@ -29,7 +29,7 @@ suite.test('ConnectionParameters initialized from environment variables', functi
   process.env['PGDATABASE'] = 'allyerbase'
   process.env['PGPASSWORD'] = 'open'
 
-  var subject = new ConnectionParameters()
+  const subject = new ConnectionParameters()
   assert.equal(subject.host, 'local', 'env host')
   assert.equal(subject.user, 'bmc2', 'env user')
   assert.equal(subject.port, 7890, 'env port')
@@ -46,7 +46,7 @@ suite.test('ConnectionParameters initialized from mix', function () {
   process.env['PGPASSWORD'] = 'open'
   delete process.env['PGPASSWORD']
   delete process.env['PGDATABASE']
-  var subject = new ConnectionParameters({
+  const subject = new ConnectionParameters({
     user: 'testing',
     database: 'zugzug',
   })
@@ -59,8 +59,8 @@ suite.test('ConnectionParameters initialized from mix', function () {
 
 suite.test('connection string parsing', function () {
   clearEnv()
-  var string = 'postgres://brian:pw@boom:381/lala'
-  var subject = new ConnectionParameters(string)
+  const string = 'postgres://brian:pw@boom:381/lala'
+  const subject = new ConnectionParameters(string)
   assert.equal(subject.host, 'boom', 'string host')
   assert.equal(subject.user, 'brian', 'string user')
   assert.equal(subject.password, 'pw', 'string password')
@@ -72,8 +72,8 @@ suite.test('connection string parsing - ssl', function () {
   // clear process.env
   clearEnv()
 
-  var string = 'postgres://brian:pw@boom:381/lala?ssl=true'
-  var subject = new ConnectionParameters(string)
+  let string = 'postgres://brian:pw@boom:381/lala?ssl=true'
+  let subject = new ConnectionParameters(string)
   assert.equal(subject.ssl, true, 'ssl')
 
   string = 'postgres://brian:pw@boom:381/lala?ssl=1'
@@ -99,15 +99,15 @@ suite.test('connection string parsing - ssl', function () {
 
 suite.test('ssl is false by default', function () {
   clearEnv()
-  var subject = new ConnectionParameters()
+  const subject = new ConnectionParameters()
   assert.equal(subject.ssl, false)
 })
 
-var testVal = function (mode, expected) {
+const testVal = function (mode, expected) {
   suite.test('ssl is ' + expected + ' when $PGSSLMODE=' + mode, function () {
     clearEnv()
     process.env.PGSSLMODE = mode
-    var subject = new ConnectionParameters()
+    const subject = new ConnectionParameters()
     assert.deepStrictEqual(subject.ssl, expected)
   })
 }
@@ -122,6 +122,6 @@ testVal('verify-full', true)
 testVal('no-verify', { rejectUnauthorized: false })
 
 // restore process.env
-for (var key in realEnv) {
+for (const key in realEnv) {
   process.env[key] = realEnv[key]
 }
diff --git a/packages/pg/test/unit/connection/error-tests.js b/packages/pg/test/unit/connection/error-tests.js
index b7496aba9..2171a25b6 100644
--- a/packages/pg/test/unit/connection/error-tests.js
+++ b/packages/pg/test/unit/connection/error-tests.js
@@ -1,14 +1,14 @@
 'use strict'
-var helper = require('./test-helper')
-var Connection = require('../../../lib/connection')
-var net = require('net')
+const helper = require('./test-helper')
+const Connection = require('../../../lib/connection')
+const net = require('net')
 const assert = require('assert')
 
 const suite = new helper.Suite()
 const { MemoryStream } = helper
 
 suite.test('connection emits stream errors', function (done) {
-  var con = new Connection({ stream: new MemoryStream() })
+  const con = new Connection({ stream: new MemoryStream() })
   assert.emits(con, 'error', function (err) {
     assert.equal(err.message, 'OMG!')
     done()
@@ -18,28 +18,28 @@ suite.test('connection emits stream errors', function (done) {
 })
 
 suite.test('connection emits ECONNRESET errors during normal operation', function (done) {
-  var con = new Connection({ stream: new MemoryStream() })
+  const con = new Connection({ stream: new MemoryStream() })
   con.connect()
   assert.emits(con, 'error', function (err) {
     assert.equal(err.code, 'ECONNRESET')
     done()
   })
-  var e = new Error('Connection Reset')
+  const e = new Error('Connection Reset')
   e.code = 'ECONNRESET'
   con.stream.emit('error', e)
 })
 
 suite.test('connection does not emit ECONNRESET errors during disconnect', function (done) {
-  var con = new Connection({ stream: new MemoryStream() })
+  const con = new Connection({ stream: new MemoryStream() })
   con.connect()
-  var e = new Error('Connection Reset')
+  const e = new Error('Connection Reset')
   e.code = 'ECONNRESET'
   con.end()
   con.stream.emit('error', e)
   done()
 })
 
-var SSLNegotiationPacketTests = [
+const SSLNegotiationPacketTests = [
   {
     testName: 'connection does not emit ECONNRESET errors during disconnect also when using SSL',
     errorMessage: null,
@@ -63,8 +63,8 @@ var SSLNegotiationPacketTests = [
 for (const tc of SSLNegotiationPacketTests) {
   suite.test(tc.testName, function (done) {
     // our fake postgres server
-    var socket
-    var server = net.createServer(function (c) {
+    let socket
+    const server = net.createServer(function (c) {
       socket = c
       c.once('data', function (data) {
         c.write(Buffer.from(tc.response))
@@ -72,7 +72,7 @@ for (const tc of SSLNegotiationPacketTests) {
     })
 
     server.listen(7778, function () {
-      var con = new Connection({ ssl: true })
+      const con = new Connection({ ssl: true })
       con.connect(7778, 'localhost')
       assert.emits(con, tc.responseType, function (err) {
         if (tc.errorMessage !== null || err) {
diff --git a/packages/pg/test/unit/connection/startup-tests.js b/packages/pg/test/unit/connection/startup-tests.js
index eaedfbad2..65cc0c0aa 100644
--- a/packages/pg/test/unit/connection/startup-tests.js
+++ b/packages/pg/test/unit/connection/startup-tests.js
@@ -1,31 +1,31 @@
 'use strict'
 const helper = require('./test-helper')
 const assert = require('assert')
-var Connection = require('../../../lib/connection')
+const Connection = require('../../../lib/connection')
 const suite = new helper.Suite()
 const test = suite.test.bind(suite)
 const { MemoryStream } = helper
 test('connection can take existing stream', function () {
-  var stream = new MemoryStream()
-  var con = new Connection({ stream: stream })
+  const stream = new MemoryStream()
+  const con = new Connection({ stream: stream })
   assert.equal(con.stream, stream)
 })
 
 test('connection can take stream factory method', function () {
-  var stream = new MemoryStream()
-  var connectionOpts = {}
-  var makeStream = function (opts) {
+  const stream = new MemoryStream()
+  const connectionOpts = {}
+  const makeStream = function (opts) {
     assert.equal(connectionOpts, opts)
     return stream
   }
   connectionOpts.stream = makeStream
-  var con = new Connection(connectionOpts)
+  const con = new Connection(connectionOpts)
   assert.equal(con.stream, stream)
 })
 
 test('using any stream', function () {
-  var makeStream = function () {
-    var stream = new MemoryStream()
+  const makeStream = function () {
+    const stream = new MemoryStream()
     stream.connect = function (port, host) {
       this.connectCalled = true
       this.port = port
@@ -34,9 +34,9 @@ test('using any stream', function () {
     return stream
   }
 
-  var stream = makeStream()
+  const stream = makeStream()
 
-  var con = new Connection({ stream: stream })
+  const con = new Connection({ stream: stream })
 
   con.connect(1234, 'bang')
 
@@ -53,7 +53,7 @@ test('using any stream', function () {
   })
 
   test('after stream connects client emits connected event', function () {
-    var hit = false
+    let hit = false
 
     con.once('connect', function () {
       hit = true
@@ -64,11 +64,11 @@ test('using any stream', function () {
   })
 
   test('after stream emits connected event init TCP-keepalive', function () {
-    var stream = makeStream()
-    var con = new Connection({ stream: stream, keepAlive: true })
+    const stream = makeStream()
+    const con = new Connection({ stream: stream, keepAlive: true })
     con.connect(123, 'test')
 
-    var res = false
+    let res = false
 
     stream.setKeepAlive = function (bit) {
       res = bit
diff --git a/packages/pg/test/unit/test-helper.js b/packages/pg/test/unit/test-helper.js
index 757c986e7..618866920 100644
--- a/packages/pg/test/unit/test-helper.js
+++ b/packages/pg/test/unit/test-helper.js
@@ -1,8 +1,8 @@
 'use strict'
-var EventEmitter = require('events').EventEmitter
+const EventEmitter = require('events').EventEmitter
 
-var helper = require('../test-helper')
-var Connection = require('../../lib/connection')
+const helper = require('../test-helper')
+const Connection = require('../../lib/connection')
 const { Client } = helper
 
 const MemoryStream = function () {
@@ -12,7 +12,7 @@ const MemoryStream = function () {
 
 helper.sys.inherits(MemoryStream, EventEmitter)
 
-var p = MemoryStream.prototype
+const p = MemoryStream.prototype
 
 p.connect = function () {
   // NOOP
@@ -36,8 +36,8 @@ p.closed = false
 p.writable = true
 
 const createClient = function () {
-  var stream = new MemoryStream()
-  var client = new Client({
+  const stream = new MemoryStream()
+  const client = new Client({
     connection: new Connection({ stream: stream }),
   })
   client.connect()
diff --git a/packages/pg/test/unit/utils-tests.js b/packages/pg/test/unit/utils-tests.js
index d514f5ad8..0e79e6265 100644
--- a/packages/pg/test/unit/utils-tests.js
+++ b/packages/pg/test/unit/utils-tests.js
@@ -1,21 +1,21 @@
 'use strict'
-var helper = require('./test-helper')
-var utils = require('./../../lib/utils')
-var defaults = require('./../../lib').defaults
+const helper = require('./test-helper')
+const utils = require('./../../lib/utils')
+const defaults = require('./../../lib').defaults
 const assert = require('assert')
 const suite = new helper.Suite()
 const test = suite.test.bind(suite)
 
 test('ensure types is exported on root object', function () {
-  var pg = require('../../lib')
+  const pg = require('../../lib')
   assert(pg.types)
   assert(pg.types.getTypeParser)
   assert(pg.types.setTypeParser)
 })
 
 test('normalizing query configs', function () {
-  var config
-  var callback = function () {}
+  let config
+  const callback = function () {}
 
   config = utils.normalizeQueryConfig({ text: 'TEXT' })
   assert.same(config, { text: 'TEXT' })
@@ -34,14 +34,14 @@ test('normalizing query configs', function () {
 })
 
 test('prepareValues: buffer prepared properly', function () {
-  var buf = Buffer.from('quack')
-  var out = utils.prepareValue(buf)
+  const buf = Buffer.from('quack')
+  const out = utils.prepareValue(buf)
   assert.strictEqual(buf, out)
 })
 
 test('prepareValues: Uint8Array prepared properly', function () {
-  var buf = new Uint8Array([1, 2, 3]).subarray(1, 2)
-  var out = utils.prepareValue(buf)
+  const buf = new Uint8Array([1, 2, 3]).subarray(1, 2)
+  const out = utils.prepareValue(buf)
   assert.ok(Buffer.isBuffer(out))
   assert.equal(out.length, 1)
   assert.deepEqual(out[0], 2)
@@ -50,8 +50,8 @@ test('prepareValues: Uint8Array prepared properly', function () {
 test('prepareValues: date prepared properly', function () {
   helper.setTimezoneOffset(-330)
 
-  var date = new Date(2014, 1, 1, 11, 11, 1, 7)
-  var out = utils.prepareValue(date)
+  const date = new Date(2014, 1, 1, 11, 11, 1, 7)
+  const out = utils.prepareValue(date)
   assert.strictEqual(out, '2014-02-01T11:11:01.007+05:30')
 
   helper.resetTimezoneOffset()
@@ -61,8 +61,8 @@ test('prepareValues: date prepared properly as UTC', function () {
   defaults.parseInputDatesAsUTC = true
 
   // make a date in the local timezone that represents a specific UTC point in time
-  var date = new Date(Date.UTC(2014, 1, 1, 11, 11, 1, 7))
-  var out = utils.prepareValue(date)
+  const date = new Date(Date.UTC(2014, 1, 1, 11, 11, 1, 7))
+  const out = utils.prepareValue(date)
   assert.strictEqual(out, '2014-02-01T11:11:01.007+00:00')
 
   defaults.parseInputDatesAsUTC = false
@@ -71,8 +71,8 @@ test('prepareValues: date prepared properly as UTC', function () {
 test('prepareValues: BC date prepared properly', function () {
   helper.setTimezoneOffset(-330)
 
-  var date = new Date(-3245, 1, 1, 11, 11, 1, 7)
-  var out = utils.prepareValue(date)
+  const date = new Date(-3245, 1, 1, 11, 11, 1, 7)
+  const out = utils.prepareValue(date)
   assert.strictEqual(out, '3246-02-01T11:11:01.007+05:30 BC')
 
   helper.resetTimezoneOffset()
@@ -82,104 +82,104 @@ test('prepareValues: 1 BC date prepared properly', function () {
   helper.setTimezoneOffset(-330)
 
   // can't use the multi-argument constructor as year 0 would be interpreted as 1900
-  var date = new Date('0000-02-01T11:11:01.007')
-  var out = utils.prepareValue(date)
+  const date = new Date('0000-02-01T11:11:01.007')
+  const out = utils.prepareValue(date)
   assert.strictEqual(out, '0001-02-01T11:11:01.007+05:30 BC')
 
   helper.resetTimezoneOffset()
 })
 
 test('prepareValues: undefined prepared properly', function () {
-  var out = utils.prepareValue(void 0)
+  const out = utils.prepareValue(void 0)
   assert.strictEqual(out, null)
 })
 
 test('prepareValue: null prepared properly', function () {
-  var out = utils.prepareValue(null)
+  const out = utils.prepareValue(null)
   assert.strictEqual(out, null)
 })
 
 test('prepareValue: true prepared properly', function () {
-  var out = utils.prepareValue(true)
+  const out = utils.prepareValue(true)
   assert.strictEqual(out, 'true')
 })
 
 test('prepareValue: false prepared properly', function () {
-  var out = utils.prepareValue(false)
+  const out = utils.prepareValue(false)
   assert.strictEqual(out, 'false')
 })
 
 test('prepareValue: number prepared properly', function () {
-  var out = utils.prepareValue(3.042)
+  const out = utils.prepareValue(3.042)
   assert.strictEqual(out, '3.042')
 })
 
 test('prepareValue: string prepared properly', function () {
-  var out = utils.prepareValue('big bad wolf')
+  const out = utils.prepareValue('big bad wolf')
   assert.strictEqual(out, 'big bad wolf')
 })
 
 test('prepareValue: simple array prepared properly', function () {
-  var out = utils.prepareValue([1, null, 3, undefined, [5, 6, 'squ,awk']])
+  const out = utils.prepareValue([1, null, 3, undefined, [5, 6, 'squ,awk']])
   assert.strictEqual(out, '{"1",NULL,"3",NULL,{"5","6","squ,awk"}}')
 })
 
 test('prepareValue: complex array prepared properly', function () {
-  var out = utils.prepareValue([{ x: 42 }, { y: 84 }])
+  const out = utils.prepareValue([{ x: 42 }, { y: 84 }])
   assert.strictEqual(out, '{"{\\"x\\":42}","{\\"y\\":84}"}')
 })
 
 test('prepareValue: date array prepared properly', function () {
   helper.setTimezoneOffset(-330)
 
-  var date = new Date(2014, 1, 1, 11, 11, 1, 7)
-  var out = utils.prepareValue([date])
+  const date = new Date(2014, 1, 1, 11, 11, 1, 7)
+  const out = utils.prepareValue([date])
   assert.strictEqual(out, '{"2014-02-01T11:11:01.007+05:30"}')
 
   helper.resetTimezoneOffset()
 })
 
 test('prepareValue: arbitrary objects prepared properly', function () {
-  var out = utils.prepareValue({ x: 42 })
+  const out = utils.prepareValue({ x: 42 })
   assert.strictEqual(out, '{"x":42}')
 })
 
 test('prepareValue: objects with simple toPostgres prepared properly', function () {
-  var customType = {
+  const customType = {
     toPostgres: function () {
       return 'zomgcustom!'
     },
   }
-  var out = utils.prepareValue(customType)
+  const out = utils.prepareValue(customType)
   assert.strictEqual(out, 'zomgcustom!')
 })
 
 test('prepareValue: buffer array prepared properly', function () {
-  var buffer1 = Buffer.from('dead', 'hex')
-  var buffer2 = Buffer.from('beef', 'hex')
-  var out = utils.prepareValue([buffer1, buffer2])
+  const buffer1 = Buffer.from('dead', 'hex')
+  const buffer2 = Buffer.from('beef', 'hex')
+  const out = utils.prepareValue([buffer1, buffer2])
   assert.strictEqual(out, '{\\\\xdead,\\\\xbeef}')
 })
 
 test('prepareValue: Uint8Array array prepared properly', function () {
-  var buffer1 = Uint8Array.from(Buffer.from('dead', 'hex'))
-  var buffer2 = Uint8Array.from(Buffer.from('beef', 'hex'))
-  var out = utils.prepareValue([buffer1, buffer2])
+  const buffer1 = Uint8Array.from(Buffer.from('dead', 'hex'))
+  const buffer2 = Uint8Array.from(Buffer.from('beef', 'hex'))
+  const out = utils.prepareValue([buffer1, buffer2])
   assert.strictEqual(out, '{\\\\xdead,\\\\xbeef}')
 })
 
 test('prepareValue: objects with complex toPostgres prepared properly', function () {
-  var customType = {
+  const customType = {
     toPostgres: function () {
       return [1, 2]
     },
   }
-  var out = utils.prepareValue(customType)
+  const out = utils.prepareValue(customType)
   assert.strictEqual(out, '{"1","2"}')
 })
 
 test('prepareValue: objects with toPostgres receive prepareValue', function () {
-  var customRange = {
+  const customRange = {
     lower: {
       toPostgres: function () {
         return 5
@@ -194,12 +194,12 @@ test('prepareValue: objects with toPostgres receive prepareValue', function () {
       return '[' + prepare(this.lower) + ',' + prepare(this.upper) + ']'
     },
   }
-  var out = utils.prepareValue(customRange)
+  const out = utils.prepareValue(customRange)
   assert.strictEqual(out, '[5,10]')
 })
 
 test('prepareValue: objects with circular toPostgres rejected', function () {
-  var customType = {
+  const customType = {
     toPostgres: function () {
       return {
         toPostgres: function () {
@@ -221,19 +221,19 @@ test('prepareValue: objects with circular toPostgres rejected', function () {
 })
 
 test('prepareValue: can safely be used to map an array of values including those with toPostgres functions', function () {
-  var customType = {
+  const customType = {
     toPostgres: function () {
       return 'zomgcustom!'
     },
   }
-  var values = [1, 'test', customType]
-  var out = values.map(utils.prepareValue)
+  const values = [1, 'test', customType]
+  const out = values.map(utils.prepareValue)
   assert.deepEqual(out, [1, 'test', 'zomgcustom!'])
 })
 
-var testEscapeLiteral = function (testName, input, expected) {
+const testEscapeLiteral = function (testName, input, expected) {
   test(testName, function () {
-    var actual = utils.escapeLiteral(input)
+    const actual = utils.escapeLiteral(input)
     assert.equal(expected, actual)
   })
 }
@@ -265,9 +265,9 @@ testEscapeLiteral(
   " E'hello \\\\ '' \" world'"
 )
 
-var testEscapeIdentifier = function (testName, input, expected) {
+const testEscapeIdentifier = function (testName, input, expected) {
   test(testName, function () {
-    var actual = utils.escapeIdentifier(input)
+    const actual = utils.escapeIdentifier(input)
     assert.equal(expected, actual)
   })
 }
diff --git a/packages/pg/test/worker/src/index.test.js b/packages/pg/test/worker/src/index.test.js
index 2bfe50c2a..637c5aec4 100644
--- a/packages/pg/test/worker/src/index.test.js
+++ b/packages/pg/test/worker/src/index.test.js
@@ -1,11 +1,11 @@
 if (parseInt(process.versions.node.split('.')[0]) < 20) {
   process.exit(0)
 }
-var helper = require('../../test-helper')
+const helper = require('../../test-helper')
 const path = require('path')
 const { unstable_dev } = require('wrangler')
 
-var suite = new helper.Suite()
+const suite = new helper.Suite()
 const assert = require('assert')
 
 suite.testAsync('Can run in Cloudflare Worker?', test())
diff --git a/packages/pg/test/worker/src/index.ts b/packages/pg/test/worker/src/index.ts
index 61597c3c2..64f1fd322 100644
--- a/packages/pg/test/worker/src/index.ts
+++ b/packages/pg/test/worker/src/index.ts
@@ -14,7 +14,7 @@ export default {
     const params = url.searchParams
     const ssl = params.has('ssl')
 
-    var client = new Client({
+    const client = new Client({
       user: env.PGUSER || env.USER,
       password: env.PGPASSWORD,
       ssl,