Add dynamicUpdate method

.gitignore

@@ -1,2 +1,3 @@
-.nyc_output
+.nyc_output/
 coverage/
+node_modules/

API.md

@@ -210,6 +210,19 @@ Update a single record. Passthrough to [DocumentClient.update](http://docs.aws.a
 
 Returns **Request**
 
+## dynamicUpdate
+
+Updates a single record, dynamically generating parts of the update statement from an object.
+Given a new object to update within a table, the necessary parameters to update every key in this new object will be generated.
+
+**Parameters**
+
+-   `newObject` **object** all of this object's properties will be used to update the row in the table
+-   `params` **object** standard update request parameters. See [DocumentClient.update](http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/DynamoDB/DocumentClient.html#update-property) for details. ExpressionAttributeNames, ExpressionAttributeValues, and UpdateExpression fields not reqiured
+-   `callback` **[function]** a function to handle the response. See [DocumentClient.update](http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/DynamoDB/DocumentClient.html#update-property) for details.
+
+Returns **Request**
+
 # CompleteRequestSet
 
 An array of [AWS.Requests](http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/Request.html)

index.js

@@ -338,7 +338,18 @@ function Dyno(options) {
      * @param {function} [callback] - a function to handle the response. See [DocumentClient.scan](http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/DynamoDB/DocumentClient.html#scan-property) for details.
      * @returns a Request if not paginating, or a ReadableStream if multiple pages were requested
      */
-    scan: require('./lib/paginated')(docClient).scan
+    scan: require('./lib/paginated')(docClient).scan,
+    /**
+     * Given a object, generates the necessary parameters to update every key in the new object within a given Dynamo table and executes the update
+     * 
+     * @instanceof
+     * @memberof client
+     * @param {object} newObject - all of this object's properties will be used to update the row in the table 
+     * @param {object} updateParams - standard parameters object for a [DocumentClient.update](http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/DynamoDB/DocumentClient.html#update-property) call, ExpressionAttributeNames, ExpressionAttributeValues, and UpdateExpression not reqiured
+     * @param {function} callback - a function to handle the response. See [DocumentClient.update](http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/DynamoDB/DocumentClient.html#update-property) for details.
+     * @returns {Request}
+     */
+    dynamicUpdate: require('./lib/update')(docClient).dynamicUpdate
   };
 
   // Drop specific functions from read/write only clients
@@ -350,6 +361,7 @@ function Dyno(options) {
     delete dynoExtensions.batchWriteItemRequests;
     delete dynoExtensions.batchWriteAll;
     delete dynoExtensions.putStream;
+    delete dynoExtensions.dynamicUpdate;
   }
 
   if (options.write) {

lib/update.js

@@ -0,0 +1,27 @@
+var _ = require('underscore');
+
+module.exports = function(client) {
+  var updates = {};
+
+  updates.dynamicUpdate = function (newObject, updateParams, callback) {
+    var expressionObject = {
+      ExpressionAttributeNames: {},
+      ExpressionAttributeValues: {}
+    };
+    var updateExpressionParts = [];
+
+    Object.keys(newObject).forEach(function (key) {
+      if (Object.keys(updateParams.Key).indexOf(key) !== -1) return;
+
+      expressionObject.ExpressionAttributeNames['#' + key] = key;
+      expressionObject.ExpressionAttributeValues[':' + key] = newObject[key];
+      updateExpressionParts.push('#' + key + ' = :' + key);
+    });
+    expressionObject.UpdateExpression = 'set ' + updateExpressionParts.join(', ');
+
+    updateParams = _.extend(updateParams, expressionObject);
+    return client.update(updateParams, callback);
+  };
+
+  return updates;
+};

test/index.test.js

@@ -27,6 +27,7 @@ test('[index] expected properties', function(assert) {
   assert.equal(typeof dyno.query, 'function', 'exposes query function');
   assert.equal(typeof dyno.scan, 'function', 'exposes scan function');
   assert.equal(typeof dyno.updateItem, 'function', 'exposes updateItem function');
+  assert.equal(typeof dyno.dynamicUpdate, 'function', 'exposes dynamicUpdate function');
   assert.equal(typeof dyno.batchGetItemRequests, 'function', 'exposes batchGetItemRequests function');
   assert.equal(typeof dyno.batchWriteItemRequests, 'function', 'exposes batchWriteItemRequests function');
   assert.equal(typeof dyno.batchGetAll, 'function', 'exposes batchGetAll function');
@@ -50,6 +51,7 @@ test('[index] expected properties', function(assert) {
   assert.equal(typeof read.query, 'function', 'read-only client exposes query function');
   assert.equal(typeof read.scan, 'function', 'read-only client exposes scan function');
   assert.equal(typeof read.updateItem, 'undefined', 'read-only client does not expose updateItem function');
+  assert.equal(typeof read.dynamicUpdate, 'undefined', 'read-only client does not expose dynamicUpdate function');
   assert.equal(typeof read.batchGetItemRequests, 'function', 'read-only client exposes batchGetItemRequests function');
   assert.equal(typeof read.batchWriteItemRequests, 'undefined', 'read-only client does not expose batchWriteItemRequests function');
   assert.equal(typeof read.batchGetAll, 'function', 'read-only client exposes batchGetAll function');
@@ -73,6 +75,7 @@ test('[index] expected properties', function(assert) {
   assert.equal(typeof write.query, 'undefined', 'write-only client does not expose query function');
   assert.equal(typeof write.scan, 'undefined', 'write-only client does not expose scan function');
   assert.equal(typeof write.updateItem, 'function', 'write-only client exposes updateItem function');
+  assert.equal(typeof write.dynamicUpdate, 'function', 'write-only client exposes dynamicUpdate function');
   assert.equal(typeof write.batchGetItemRequests, 'undefined', 'write-only client does not expose batchGetItemRequests function');
   assert.equal(typeof write.batchWriteItemRequests, 'function', 'write-only client exposes batchWriteItemRequests function');
   assert.equal(typeof write.batchGetAll, 'undefined', 'write-only client does not expose batchGetAll function');
@@ -99,6 +102,7 @@ test('[index] expected properties', function(assert) {
   assert.equal(typeof multi.query, 'function', 'multi-client exposes query function');
   assert.equal(typeof multi.scan, 'function', 'multi-client exposes scan function');
   assert.equal(typeof multi.updateItem, 'function', 'multi-client exposes updateItem function');
+  assert.equal(typeof multi.dynamicUpdate, 'function', 'multi-client exposes dynamicUpdate function');
   assert.equal(typeof multi.batchGetItemRequests, 'function', 'exposes batchGetItemRequests function');
   assert.equal(typeof multi.batchWriteItemRequests, 'function', 'exposes batchWriteItemRequests function');
   assert.equal(typeof multi.batchGetAll, 'function', 'exposes batchGetAll function');

test/update.test.js

@@ -0,0 +1,79 @@
+var test = require('tape');
+var testTables = require('./test-tables');
+var dynamodb = require('dynamodb-test')(test, 'dyno', testTables.idhash);
+var Dyno = require('..');
+var Update = require('../lib/update');
+var _ = require('underscore');
+
+var fixtures = _.range(10).map(function (i) {
+  return {
+    id: i.toString(),
+    idPower2: Math.pow(i, 2),
+    text: 'string'
+  };
+});
+
+test('[update] properties', function (assert) {
+  var update = Update(dynamodb.dynamodb);
+  assert.equal(typeof update.dynamicUpdate, 'function', 'exposes dynamicUpdate function');
+  assert.end();
+});
+
+dynamodb.start();
+
+dynamodb.test('[update] dynamicUpdate - update all fields', fixtures, function (assert) {
+  var dyno = Dyno({
+    table: dynamodb.tableName,
+    region: 'local',
+    endpoint: 'http://localhost:4567'
+  });
+
+  var newObject = {
+    id: '2',
+    idPower2: -99,
+    text: 'update string'
+  };
+  var updateParams = {
+    TableName: dynamodb.tableName,
+    Key: { id: '2' },
+    ReturnValues: 'ALL_NEW'
+  };
+
+  dyno.dynamicUpdate(newObject, updateParams, function (err, response) {
+    assert.ifError(err, 'dynamicUpdate errored');
+    assert.deepEqual(response, { Attributes: { id: '2', idPower2: -99, text: 'update string' } }, 'expected new values');
+    assert.end();
+  });
+});
+
+dynamodb.test('[update] dynamicUpdate - only add new field', fixtures, function (assert) {
+  var dyno = Dyno({
+    table: dynamodb.tableName,
+    region: 'local',
+    endpoint: 'http://localhost:4567'
+  });
+
+  var newObject = {
+    id: '2',
+    newDateField: '2017-10-31'
+  };
+  var updateParams = {
+    TableName: dynamodb.tableName,
+    Key: { id: '0' },
+    ReturnValues: 'ALL_NEW'
+  };
+
+  var expectedRow = { id: '0', idPower2: 0, newDateField: '2017-10-31', text: 'string' };
+  dyno.dynamicUpdate(newObject, updateParams, function (err, response) {
+    assert.ifError(err, 'dynamicUpdate errored');
+    assert.deepEqual(response, { Attributes: expectedRow }, 'expected new values');
+    dyno.query({ KeyConditionExpression: 'id = :id', ExpressionAttributeValues: { ':id': '0' } }, function (err, queryResponse) {
+      assert.ifError(err, 'query error');
+      assert.deepEqual(queryResponse.Items, [expectedRow], 'expected query response');
+      assert.end();
+    });
+  });
+});
+
+dynamodb.delete();
+dynamodb.close();