Merge pull request #5 from cgmartin/helpers

feat(): Custom Handlebars extensions

.eslintrc.js

@@ -128,7 +128,7 @@ module.exports = {
         "no-param-reassign": "off",
         "no-path-concat": "error",
         "no-plusplus": "error",
-        "no-process-env": "error",
+        "no-process-env": "off",
         "no-process-exit": "error",
         "no-proto": "error",
         "no-restricted-globals": "error",
@@ -175,7 +175,7 @@ module.exports = {
         "prefer-reflect": "off",
         "prefer-rest-params": "off",
         "prefer-spread": "error",
-        "prefer-template": "error",
+        "prefer-template": "off",
         "quote-props": "off",
         "quotes": "off",
         "radix": "error",

README.md

@@ -9,8 +9,8 @@ A simple templating utility, akin to [`envsubst`](http://linuxcommand.org/man_pa
 
 Environment variables are used as the data input to a Handlebars template:
 ```
-$ export WORLD=world
-$ echo "Hello {{WORLD}}" | envhandlebars
+$ export NAME=world
+$ echo "Hello {{NAME}}" | envhandlebars
 Hello world
 ```
 
@@ -50,7 +50,8 @@ Output:
 Hello world!
 ```
 
-See the [if block helper](http://handlebarsjs.com/builtin_helpers.html#conditionals) for more information.
+See the [if block helper](http://handlebarsjs.com/builtin_helpers.html#conditionals) docs page for more information.
+
 
 ### Iterators
 
@@ -99,7 +100,8 @@ Output:
 Chris Martin, John Papa, Shayne Boyer!
 ```
 
-See the [each block helper](http://handlebarsjs.com/builtin_helpers.html#iteration) for more information.
+See the [each block helper](http://handlebarsjs.com/builtin_helpers.html#iteration) docs page for more information.
+
 
 ## Docker Usage
 
@@ -136,6 +138,33 @@ For alpine-based images:
 RUN apk add --update nodejs && npm i -g envhandlebars
 ```
 
+## Custom Helpers or Partials
+
+**(New in v1.3.0+)**
+
+Custom Mustache helpers and partials can be implemented by extending the `envhandlebars` module with your own Node.js wrapper script:
+
+```javascript
+#!/usr/bin/env node
+// Script: `myenvhandlebars`
+'use strict';
+var envhandlebars = require('envhandlebars');
+
+// The Handlebars context is passed into this function
+// for registering helpers, partials or other extensions.
+function extendHandlebars(Handlebars) {
+    Handlebars.registerHelper('fullName', function(first, last) {
+        return last + ', ' + first;
+    });
+}
+
+envhandlebars({
+    extendHandlebars: extendHandlebars
+});
+```
+
+See the [custom helpers](http://handlebarsjs.com/#helpers) docs page for more information.
+
 ## License
 
 [MIT License](http://cgm.mit-license.org/)

bin/envhandlebars

@@ -1,20 +1,9 @@
 #!/usr/bin/env node
 /* eslint no-process-env: 0, no-process-exit: 0, no-console: 0 */
 'use strict';
-var bin = require('../index.js');
+var envhandlebars = require('../index.js');
 
 // Provide a title to the process in `ps`
 process.title = 'envhandlebars';
 
-bin({
-    env: process.env,
-    stdin: process.stdin,
-    stdout: process.stdout,
-    stderr: process.stderr,
-    argv: process.argv
-}, function(err) {
-    if (err) {
-        console.error(err);
-        process.exit(1);
-    }
-});
+envhandlebars();

index.js

@@ -3,8 +3,33 @@ var concat = require('concat-stream');
 var Handlebars = require('handlebars');
 var util = require('util');
 
-module.exports = function bin(opts, cb) {
+module.exports = function envhandlebars(opts, cb) {
+    // Defaults
+    if (!cb && typeof opts === 'function') {
+        cb = opts;
+        opts = {};
+    }
+    opts = opts || {};
+    opts.env = opts.env || process.env;
+    opts.exit = opts.exit || process.exit;
+    opts.stdin = opts.stdin || process.stdin;
+    opts.stdout = opts.stdout || process.stdout;
+    opts.stderr = opts.stderr || process.stderr;
+    opts.argv = opts.argv || process.argv;
+
+    cb = cb || function(err) {
+        if (err) {
+            opts.stderr.write(util.format.call(null, err));
+            opts.exit(1);
+        }
+    };
+
+    // Allow helpers or other extensions to be applied
+    if (typeof opts.extendHandlebars === 'function') {
+        opts.extendHandlebars(Handlebars);
+    }
 
+    // Stream stdin through handlebars template procesing
     opts.stdin.setEncoding('utf8');
     opts.stdin.on('error', handleError);
     opts.stdin.pipe(concat(applyTemplate));

package.json

@@ -1,6 +1,6 @@
 {
   "name": "envhandlebars",
-  "version": "1.2.1",
+  "version": "1.3.0",
   "description": "Simple handlebars templating for configuration files using environment variables",
   "main": "index.js",
   "scripts": {

test/index.spec.js

@@ -16,7 +16,7 @@ describe('envhandlebars', function() {
         argv = [
             'node',
             path.join(__dirname, "../bin/envhandlebars")
-        ]
+        ];
     });
 
     describe('basic expressions', function () {
@@ -128,4 +128,29 @@ describe('envhandlebars', function() {
             });
         });
     });
+
+    describe('handlebars extensions', function () {
+        it('should register helper', function (done) {
+            var stdin = new stream.ReadableStream(
+                "Hello {{fullName FIRST_NAME LAST_NAME}}"
+            );
+            function registerHelpers(Handlebars) {
+                Handlebars.registerHelper('fullName', function(first, last) {
+                    return last + ', ' + first;
+                });
+            }
+
+            fixture({
+                env: { FIRST_NAME: 'first', LAST_NAME: 'last' },
+                stdin: stdin, stdout: stdout, stderr: stderr,
+                argv: argv,
+                extendHandlebars: registerHelpers
+            }, function (err) {
+                assert.ifError(err);
+                assert.equal(stdout.toString(), 'Hello last, first');
+                done();
+            });
+        });
+    });
+
 });