Initial commit

Author: jedrichards

.gitignore

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+node_modules

README.md

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+# ES6
+
+> ES6 feature documentation and examples
+
+Run all the examples,
+
+```sh
+npm start
+```
+
+Run a particular example,
+
+```sh
+npm start --es6:example=arrow-functions
+```
+
+Watch an example and re-run when it changes,
+
+```sh
+npm run watch --es6:example=arrow-functions
+```
+
+## Table of contents
+
+- [Arrow functions](#arrow-functions)
+
+## Arrow functions
+
+Arrow functions have a concise function syntax, and their `this` value is lexically bound to their enclosing scope.
+
+```js
+var add = (a,b) => a+b;
+add(1,1); // 2
+```
+> When the arrow function body is a single expression it is implicitly returned.
+
+```js
+var odd = n => n % 2;
+odd(2); // 0
+```
+> When the arrow function has only one argument the parens can be omitted.
+
+```js
+var ran = () => Math.random();
+ran() // 0.265058204298839
+```
+> When the arrow function has no arguments you need the empty `()`.
+
+```js
+var transform = s => {
+  s = s.toUpperCase();
+  return s + s;
+}
+transform('a'); // AA
+```
+> When the arrow function body has multiple statements then `{}` are required.
+
+```js
+function Counter () {
+  this.count = 0;
+  setInterval(() => this.count++, 1000);
+}
+```
+> The arrow function's `this` value is bound to the enclosing scope, so no more need for `var self = this`.
+
+```js
+var lengths = ['one', 'two', 'three'].map(s => s.length);
+// [3, 3, 5]
+```
+> Arrow functions can be used to write iterators and map functions quite concisely.

index.js

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+require('babel/register');
+
+var chalk = require('chalk');
+var fs = require('fs');
+
+var example = process.env.npm_package_config_example;
+
+if ( example ) {
+    run(example);
+} else {
+    runAll();
+}
+
+function run (example) {
+    console.log('\n' + chalk.yellow(example) + '\n');
+    require('./js/' + example);
+}
+
+function runAll () {
+    var examples = fs.readdirSync('./js');
+    examples.forEach(run);
+}

js/arrow-functions.js

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+var assert = require('assert');
+
+// Simple
+
+var add = (a,b) => a+b;
+
+assert.equal(add(1,1),2);
+
+// Single arg
+
+var odd = n => n % 2;
+
+assert.equal(odd(2),false);
+assert.equal(odd(3),true);
+console.log(Math.random());
+// Lexical this
+
+function TimeoutTest () {
+    this.count = 0;
+    setTimeout(() => this.count++, 100);
+    setTimeout(() => assert.equal(this.count,1), 200);
+}
+
+var timeoutTest = new TimeoutTest();
+
+// Map
+
+var lengths = ['one', 'two', 'three'].map(s => s.length);
+assert.deepEqual(lengths, [3, 3, 5]);

package.json

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+{
+  "name": "es6",
+  "version": "0.0.1",
+  "description": "ES6 Features",
+  "main": "index.js",
+  "scripts": {
+    "start": "node index.js",
+    "watch": "node watch.js"
+  },
+  "dependencies": {
+    "babel": "^5.0.12",
+    "chalk": "^1.0.0",
+    "nodemon": "^1.3.7"
+  },
+  "engines": {
+    "node": "^0.12.0",
+    "npm": "^2.6.0"
+  }
+}

watch.js

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+var nodemon = require('nodemon');
+
+var example = process.env.npm_package_config_example;
+
+nodemon({
+    exec: 'npm start --es6:example=' + example,
+    watch: ['js']
+});