Merge pull request #404 from thejameskyle/docs

Add new documentation
This commit is contained in:
Sebastian McKenzie 2015-01-06 18:44:14 +11:00
commit 6a560cea25
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# Browser
A browser version of 6to5 is available from `browser.js` inside the 6to5
directory in an npm release.
## Scripts
While it's not recommended for serious use, when the browser version is included
all scripts with the type `text/ecmascript-6` and `text/6to5` are automatically
compiled and ran.
For example:
```html
<script src="node_modules/6to5/browser.js"></script>
<script type="text/6to5">
class Test {
test() {
return "test";
}
}
var test = new Test;
test.test();
</script>
```
## Build
You can build a browser version of the compiler by running the following in the
6to5 directory:
```sh
$ make build
```
This will output the files `dist/6to5.js` and `dist/6to5.min.js`.
## Test
To test 6to5 in your browser run:
```sh
$ make test-browser
```
And open `test/browser.html` in your browser if it doesn't open automatically.
## API
### to5.transform(code, [opts])
See [options](usage.md#options) for additional documentation.
```javascript
to5.transform("class Test {}").code;
```
### to5.run(code, [opts])
See [options](usage.md#options) for additional documentation.
```javascript
to5.run("class Test {}");
```

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# Caveats
---
layout: docs
title: Caveats
description: Just some things to keep in mind when using 6to5.
permalink: /docs/caveats/
redirect_from: /caveats.html
---
## Polyfills
In order for certain features to work they require certain polyfills. You can
satisfy **all** 6to5 feature requirements by using the included
@ -35,10 +43,10 @@ If you're inheriting from a class then static properties are inherited from it
via [\_\_proto\_\_](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/proto),
this is widely supported but you may run into problems with much older browsers.
**NOTE:** `__proto__` is not supported in IE <= 10 so static properties
**NOTE:** `__proto__` is not supported on IE <= 10 so static properties
**will not** be inherited. A possible workaround is to use `super();`:
```javascript
```js
class Foo {
static foo() {
@ -52,7 +60,7 @@ class Bar extends Foo {
}
```
## Getters/setters (8 and below)
### Getters/setters (8 and below)
In IE8 `Object.defineProperty` can only be used on DOM objects. This is
unfortunate as it's required to set getters and setters. Due to this if

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# Differences
---
layout: docs
title: Compare
description: Differences between 6to5 and other ES6 transpilers.
permalink: /docs/compare/
redirect_from: /differences.html
---
There are three main points that separate 6to5 from all other transpilers.
## Differences
### Readable code
@ -12,13 +18,13 @@ is concerned with making sure it works **and** is readable at the same time.
For example, given the following array comprehension:
```javascript
```js
var seattlers = [for (c of customers) if (c.city == "Seattle") { name: c.name, age: c.age }];
```
is generated to the following with 6to5:
```javascript
```js
var seattlers = Array.from(customers).filter(function (c) {
return c.city == "Seattle";
}).map(function (c) {
@ -31,7 +37,7 @@ var seattlers = Array.from(customers).filter(function (c) {
The following is what Traceur generates:
```javascript
```js
var seattlers = (function() {
var c;
var $__20 = 0,
@ -49,8 +55,8 @@ var seattlers = (function() {
}());
```
As you can tell, it's not very pretty. Instead of mapping directly to a
runtime, like other transpilers, 6to5 maps directly to the equivalent ES5.
As you can tell, it's not very pretty. Instead of mapping directly to a runtime,
like other transpilers, 6to5 maps directly to the equivalent ES5.
Sometimes there are little inline functions that 6to5 needs. These are
placed at the top of your file much like coffee-script does. If these

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## Experimental
6to5 also has experimental support for ES7 proposals. You can enable this with
the `experimental: true` option when using the [Node API](#node) or
`--experimental` when using the [CLI](#cli).
**WARNING:** These proposals are subject to change so use with
**extreme caution**.

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# Features
## Abstract references ([experimental](experimental.md)) ([spec](https://github.com/zenparsing/es-abstract-refs))
```javascript
foo::bar;
foo::bar = baz;
delete foo::bar;
```
## Array comprehensions ([experimental](experimental.md))
```javascript
var results = [for (c of customers) if (c.city == "Seattle") { name: c.name, age: c.age }]
```
## Arrow functions
```javascript
// Expression bodies
var odds = evens.map(v => v + 1);
var nums = evens.map((v, i) => v + i);
// Statement bodies
nums.forEach(v => {
if (v % 5 === 0)
fives.push(v);
});
// Lexical this
var bob = {
_name: "Bob",
_friends: [],
printFriends() {
this._friends.forEach(f => {
console.log(this._name + " knows " + f);
});
}
};
```
## Async functions ([experimental](experimental.md)) ([spec](https://github.com/lukehoban/ecmascript-asyncawait))
```javascript
async function chainAnimationsAsync(elem, animations) {
for (var anim of animations) {
await anim(elem);
}
}
```
## Async generator functions ([experimental](experimental.md)) ([spec](https://github.com/jhusain/asyncgenerator))
```javascript
```
## Classes
```javascript
class SkinnedMesh extends THREE.Mesh {
constructor(geometry, materials) {
super(geometry, materials);
this.idMatrix = SkinnedMesh.defaultMatrix();
this.bones = [];
this.boneMatrices = [];
//...
}
update(camera) {
//...
super.update();
}
static defaultMatrix() {
return new THREE.Matrix4();
}
}
```
## Computed property names
```javascript
var foo = "foo";
var bar = "bar";
var obj = {
["foo" + bar]: "heh",
["bar" + foo]: "noo",
foo: "foo",
bar: "bar"
};
```
## Constants
```javascript
const MULTIPLIER = 5;
console.log(2 * MULTIPLIER);
MULTIPLIER = 6; // error
var MULTIPLIER; // error
```
## Default parameters
```javascript
function f(x, y = 12) {
// y is 12 if not passed (or passed as undefined)
return x + y;
}
f(3) == 15
```
## Destructuring
```javascript
// list matching
var [a, , b] = [1,2,3];
// object matching
var { op: a, lhs: { op: b }, rhs: c } = getASTNode();
// object matching shorthand
// binds `op`, `lhs` and `rhs` in scope
var { op, lhs, rhs } = getASTNode();
// Can be used in parameter position
function g({ name: x }) {
console.log(x);
}
g({ name: 5 });
// Fail-soft destructuring
var [a] = [];
a === undefined;
```
## Exponentiation operator ([experimental](experimental.md)) ([spec](https://github.com/rwaldron/exponentiation-operator))
```javascript
var a = 2;
a **= 2;
var squared = 2 ** 2;
```
## For-of
```javascript
for (var i of [1, 2, 3]) {
console.log(i * i);
}
```
## Generators
```javascript
function* fibonacci() {
var pre = 0, cur = 1;
for (;;) {
var temp = pre;
pre = cur;
cur += temp;
yield cur;
}
}
for (var n of fibonacci()) {
// truncate the sequence at 1000
if (n > 1000) break;
console.log(n);
}
```
## Generator comprehensions ([experimental](experimental.md))
```javascript
var nums = [1, 2, 3, 4, 5, 6];
var multiples = (for (i of nums) if (i % 2) i * i);
assert.equal(multiples.next().value, 1);
assert.equal(multiples.next().value, 9);
assert.equal(multiples.next().value, 25);
```
## Let scoping
```javascript
for (let i in arr) {
let v = arr[i];
}
```
## Modules
```javascript
import "foo";
import foo from "foo";
import * as foo from "foo";
import {bar} from "foo";
import {foo as bar} from "foo";
export { test };
export var test = 5;
export function test() {}
export default test;
```
## Numeric literals
```javascript
0b111110111 === 503; // true
0o767 === 503; // true
```
## Object spread/rest ([experimental](experimental.md)) ([spec](https://github.com/sebmarkbage/ecmascript-rest-spread))
```javascript
var n = { x, y, ...z };
var { x, y, ...z } = { x: 1, y: 2, a: 3, b: 4 };
```
## Property method assignment
```javascript
var obj = {
foo() {
return "foobar";
},
get bar() {
return this._bar;
},
set bar(val) {
this._bar = val;
}
};
```
## Property name shorthand
```javascript
function f(x, y) {
return { x, y };
}
```
## Rest parameters
```javascript
function f(x, ...y) {
// y is an Array
return x * y.length;
}
f(3, "hello", true) == 6
```
## Spread
```javascript
function f(x, y, z) {
return x + y + z;
}
// Pass each elem of array as argument
f(...[1,2,3]) == 6
```
## Template literals
```javascript
var x = 5;
var y = 10;
console.log(`${x} + ${y} = ${x + y}`); // "5 + 10 = 15"
```
## Unicode regex
```javascript
var string = 'foo💩bar';
var match = string.match(/foo(.)bar/u);
console.log(match[1]);
```

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**6to5** turns ES6+ code into vanilla ES5, so you can use next generation features **today.**
- **Readable** - formatting is retained if possible so your generated code is as similar as possible.
- **Extensible** - with a large range of [plugins](plugins.md) and **browser support**.
- **Lossless** - **source map support** so you can debug your compiled code with ease.
- **Compact** - maps directly to the equivalent ES5 with **no runtime**[\*](caveats.md).
## Installation
It's as easy as:
$ npm install -g 6to5
## Usage
Once you've installed 6to5, there are multiple paths you can take depending on
how you want to use it.
6to5 will simply compile your ES6+ script to ES5 if you pass it as an argument
to the command-line tool `6to5`:
```sh
$ 6to5 script.js
```
If you have a file written using ES6+ and you just want to run it, `6to5-node`
has you covered:
```sh
$ 6to5-node script.js
```
And it doesn't end here! To see all the ways you can use 6to5, check out the
[Usage](http://6to5.github.io/usage.html) page.
## [Features](features.md)
- [Abstract references](features.md#abstract-references) ([experimental](experimental.md))
- [Array comprehension](features.md#array-comprehension) ([experimental](experimental.md))
- [Async functions](features.md#async-functions) ([experimental](experimental.md))
- [Async generator functions](features.md#async-generator-functions) ([experimental](experimental.md))
- [Arrow functions](features.md#arrow-functions)
- [Classes](features.md#classes)
- [Computed property names](features.md#computed-property-names)
- [Constants](features.md#constants)
- [Default parameters](features.md#default-parameters)
- [Destructuring](features.md#destructuring)
- [Exponentiation operator](features.md#exponentiation-operator) ([experimental](experimental.md))
- [For-of](features.md#for-of)
- [Generators](features.md#generators)
- [Generator comprehension](features.md#generator-comprehension) ([experimental](experimental.md))
- [Let scoping](features.md#let-scoping)
- [Modules](features.md#modules)
- [Numeric literals](features.md#numeric-literals)
- [Object rest/spread](features.md#object-rest-spread) ([experimental](experimental.md))
- [Property method assignment](features.md#property-method-assignment)
- [Property name shorthand](features.md#property-name-shorthand)
- [React/JSX](react.md)
- [Rest parameters](features.md#rest-parameters)
- [Spread](features.md#spread)
- [Template literals](features.md#template-literals)
- [Unicode regex](features.md#unicode-regex)

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# Playground
Playground is a proving ground for **possible** ES7 proposals.
**NOTE: These features are in no way endorsed by Ecma International and are not a part of ES6. They might become a part of ECMAScript in the future.**
## Usage
$ 6to5 --playground
```javascript
to5.transform("code", { playground: true });
```
**NOTE:** Enabling `playground` also enables [experimental support](experimental.md).
## Features
* [Memoization operator](#memoization-operator)
* [Method binding](#method-binding)
* [Method binding function shorthand](#method-binding-function-shorthand)
* [Object getter memoization](#object-getter-memoization)
* [This shorthand](#this-shorthand)
### Memoization assignment operator
The memoization assignment operator allows you to lazily set an object property.
It checks whether there's a property defined on the object and if there isn't then
the right hand value is set.
This means that `obj.x` in the following `var x = { x: undefined }; obj.x ?= 2;`
will still be `undefined` because it's already been defined on the object.
```javascript
var obj = {};
obj.x ?= 2;
obj.x; // 2
obj = { x: 1 };
obj.x ?= 2;
obj.x; // 1
obj = { x: undefined }
obj.x ?= 2;
obj.x; // undefined
```
```javascript
var obj = {};
obj.x ?= 2;
```
equivalent to
```javascript
var obj = {};
if (!Object.prototype.hasOwnProperty.call(obj, "x")) obj.x = 2;
```
### Method binding
```javascript
var fn = obj#method;
var fn = obj#method("foob");
```
equivalent to
```javascript
var fn = obj.method.bind(obj);
var fn = obj.method.bind(obj, "foob");
```
### Method binding function shorthand
```javascript
["foo", "bar"].map(#toUpperCase); // ["FOO", "BAR"]
[1.1234, 23.53245, 3].map(#toFixed(2)); // ["1.12", "23.53", "3.00"]
```
equivalent to
```javascript
["foo", "bar"].map(function (val) { return val.toUpperCase(); });
[1.1234, 23.53245, 3].map(function (val) { return val.toFixed(2); });
```
### Object getter memoization
```javascript
var foo = {
memo bar() {
return complex();
}
};
class Foo {
memo bar() {
return complex();
}
}
```
equivalent to
```javascript
var foo = {
get bar() {
return Object.defineProperty(this, "bar", {
value: complex(),
enumerable: true,
configurable: true,
writable: true
}).bar;
}
};
class Foo {
get bar() {
return Object.defineProperty(this, "bar", {
value: complex(),
enumerable: true,
configurable: true,
writable: true
}).bar;
}
}
```
### This shorthand
```javascript
@foo
```
equivalent to
```javascirpt
this.foo
```

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# Plugins
## Build systems
- [Broccoli](https://github.com/6to5/broccoli-6to5-transpiler)
- [Browserify](https://github.com/6to5/6to5ify)
- [Brunch](https://github.com/6to5/6to5-brunch)
- [Duo](https://github.com/6to5/duo6to5)
- [Gobble](https://github.com/6to5/gobble-6to5)
- [Gulp](https://github.com/6to5/gulp-6to5)
- [Grunt](https://github.com/6to5/grunt-6to5)
- [Sprockets](https://github.com/josh/sprockets-es6) or via [Browserify](https://github.com/6to5/6to5-rails)
- [webpack](https://github.com/6to5/6to5-loader)
## Integrations
- [Isparta](https://github.com/douglasduteil/isparta) - Code coverage with `karma` and `instanbul` using 6to5
- [JSXHint](https://github.com/STRML/JSXHint) - A wrapper around JSHint to allow linting of JSX files
## Bridges
- [Ruby](https://github.com/6to5/6to5-ruby)
## Testing
- [Jest](https://github.com/6to5/6to5-jest)
- [Karma](https://github.com/6to5/karma-6to5-preprocessor)
- [Mocha](https://github.com/6to5/6to5-mocha)
## Misc
- [Connect](https://github.com/6to5/6to5-connect)
- [Jade](https://github.com/6to5/jade-6to5)

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# Polyfill
6to5 includes a polyfill that includes a custom
[regenerator runtime](https://github.com/facebook/regenerator/blob/master/runtime.js) and
[core.js](https://github.com/zloirock/core-js).
This will emulate a full ES6 environment. This polyfill is automatically loaded
when using [6to5-node](usage.md#node) and [6to5/register](usage.md#register-hook).
## Usage
### Node/Browserify
You need to include the polyfill require at the top the **entry point** to your
application.
```javascript
require("6to5/polyfill");
```
Fortunately, this is automatically loaded when using:
```javascript
require("6to5/register");
```
### Browser
Available from the `browser-polyfill.js` file within the 6to5 directory of an
npm release. This needs to be included **before** all your compiled 6to5 code.
You can either prepend it to your compiled code or include it in a `<script>`
before it.
**NOTE:** Do not `require` this via browserify etc, use `6to5/polyfill`.

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# React/JSX
6to5 has built-in support for React v0.12. Tags are automatically transformed to
their equivalent `React.createElement(...)` and `displayName` is automatically
inferred and added to all `React.createClass` calls.
## Blacklist
To disable this behaviour add `react` to your blacklist:
```javascript
to5.transform("code", { blacklist: ["react"] });
```
```sh
$ 6to5 --blacklist react
```

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doc/setup.md Normal file
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---
layout: docs
title: Setup
description: Guides on how to setup 6to5 in whatever environment you might be working in.
permalink: /docs/setup/
redirect_from: /plugins.html
---
<blockquote class="to5-callout to5-callout-info">
<h4>Find your guide</h4>
<p>
It doesn't matter if you're using Node.js or Rails, Gulp or Grunt, there's likely a guide on
this page to help guide you. Go ahead and <span class="label label-info">&#8984; + F</span>
whatever you're looking for. If it doesn't happen to be on this page you might want to stop by
our <a href="https://gitter.im/6to5/6to5">support chat</a>.
</p>
</blockquote>
## Node.js
### CLI
**Install**
```sh
$ npm install --global 6to5
```
**Usage**
```sh
$ 6to5 script.js
```
<blockquote class="to5-callout to5-callout-info">
<p>
For full documentation on the 6to5 CLI see the
<a href="/docs/usage/cli/">usage docs</a>.
</p>
</blockquote>
### Require Hook
**Install**
```sh
$ npm install 6to5
```
**Usage**
All subsequent files required by node with the extensions `.es6` and `.js` will
be transformed by 6to5. The polyfill specified in [Polyfill](polyfill.md) is
also required.
```javascript
require('6to5/register');
```
<blockquote class="to5-callout to5-callout-info">
<p>
For full documentation on the 6to5 require hook see the
<a href="/docs/usage/require/">usage docs</a>.
</p>
</blockquote>
## Rails
### Sprockets
<blockquote class="to5-callout to5-callout-info">
<p>
See <strong>sprockets-es6</strong>'s
<a href="https://github.com/josh/sprockets-es6">repo</a> for more info. If
you find any bugs please
<a href="https://github.com/josh/sprockets-es6/issues">report them</a>.
</p>
<p>
<em>Issues with the output should be reported on the 6to5
<a href="https://github.com/6to5/6to5/issues">issue tracker</a></em>.
</p>
</blockquote>
**Install**
```sh
$ gem install sprockets-es6
```
**Usage**
```rb
# Gemfile
gem 'sprockets'
gem 'sprockets-es6'
```
```rb
require 'sprockets/es6'
```
## Build Systems
### Brocolli
<blockquote class="to5-callout to5-callout-info">
<p>
See <strong>broccoli-6to5-transpiler</strong>'s
<a href="https://github.com/6to5/broccoli-6to5-transpiler">repo</a> for more
info. If you find any bugs please
<a href="https://github.com/6to5/broccoli-6to5-transpiler/issues">report
them</a>.
</p>
<p>
<em>Issues with the output should be reported on the 6to5
<a href="https://github.com/6to5/6to5/issues">issue tracker</a></em>.
</p>
</blockquote>
**Install**
```sh
$ npm install --save-dev broccoli-6to5-transpiler
```
**Usage**
```js
var to5Transpiler = require('broccoli-6to5-transpiler');
var scriptTree = to5Transpiler(inputTree, options);
```
<blockquote class="to5-callout to5-callout-warning">
<h4>Source maps</h4>
<p>
Currently this plugin only support inline source maps. If you need separate
source map feature, we welcome you to submit a pull request.
</p>
</blockquote>
### Browserify
<blockquote class="to5-callout to5-callout-info">
<p>
See <strong>6to5ify</strong>'s
<a href="https://github.com/6to5/6to5ify">repo</a> for more info. If you
find any bugs please
<a href="https://github.com/6to5/6to5ify/issues">report them</a>.
</p>
<p>
<em>Issues with the output should be reported on the 6to5
<a href="https://github.com/6to5/6to5/issues">issue tracker</a></em>.
</p>
</blockquote>
**Install**
```sh
$ npm install --save-dev 6to5ify
```
**Usage via CLI**
```sh
$ browserify script.js -t 6to5ify --outfile bundle.js
```
**Usage via Node.js**
```js
browserify({ debug: true })
.transform(to5ify);
```
Or a more complete example:
```js
var fs = require('fs');
var browserify = require('browserify');
var to5ify = require('6to5ify');
browserify({ debug: true })
.transform(to5ify)
.require('./script.js', { entry: true })
.bundle()
.on('error', function (err) { console.log('Error: ' + err.message); })
.pipe(fs.createWriteStream("bundle.js"));
```
**Passing Options**
```sh
$ browserify -d -e script.js -t [ 6to5ify --blacklist generators ]
```
```js
browserify().transform(to5ify.configure({
blacklist: ['generators']
}))
```
<blockquote class="to5-callout to5-callout-info">
<h4>More info</h4>
<p>
For more information see the
<a href="https://github.com/6to5/6to5ify">6to5ify README</a>
</p>
</blockquote>
### Brunch
<blockquote class="to5-callout to5-callout-info">
<p>
See <strong>6to5-brunch</strong>'s
<a href="https://github.com/6to5/6to5-brunch">repo</a> for more info. If you
find any bugs please
<a href="https://github.com/6to5/6to5-brunch/issues">report them</a>.
</p>
<p>
<em>Issues with the output should be reported on the 6to5
<a href="https://github.com/6to5/6to5/issues">issue tracker</a></em>.
</p>
</blockquote>
**Install**
```sh
$ npm install --save-dev 6to5-brunch
```
**Configuring**
Set 6to5 options in your brunch config (such as `brunch-config.coffee`) except
for `filename` and `sourceMap` which are handled internally.
```coffee
plugins:
ES6to5:
whitelist: ['arrowFunctions']
format:
semicolons: false
```
### Duo
<blockquote class="to5-callout to5-callout-info">
<p>
See <strong>duo-6to5</strong>'s
<a href="https://github.com/6to5/duo-6to5">repo</a> for more info. If you
find any bugs please
<a href="https://github.com/6to5/duo-6to5/issues">report them</a>.
</p>
<p>
<em>Issues with the output should be reported on the 6to5
<a href="https://github.com/6to5/6to5/issues">issue tracker</a></em>.
</p>
</blockquote>
**Install**
```sh
$ npm install --save-dev duo-6to5
```
**Usage via CLI**
```sh
$ duo --use duo-6to5
```
**Usage via Node.js**
```js
Duo(root)
.entry(entry)
.use(to5)
.run(fn);
```
### Gobble
<blockquote class="to5-callout to5-callout-info">
<p>
See <strong>gobble-6to5</strong>'s
<a href="https://github.com/6to5/gobble-6to5">repo</a> for more info. If you
find any bugs please
<a href="https://github.com/6to5/gobble-6to5/issues">report them</a>.
</p>
<p>
<em>Issues with the output should be reported on the 6to5
<a href="https://github.com/6to5/6to5/issues">issue tracker</a></em>.
</p>
</blockquote>
**Install**
```sh
$ npm install --save-dev gobble-6to5
```
**Usage**
The `options` argument, if specified, is passed to 6to5.
```
var gobble = require('gobble');
module.exports = gobble('src').transform('6to5', options);
```
**Source maps**
Sourcemaps are created by default (all the relevant information is filled in by
Gobble, you don't need to specify `sourceMapName` options etc). If you don't
want that, pass `sourceMap: false`.
### Grunt
<blockquote class="to5-callout to5-callout-info">
<p>
See <strong>grunt-6to5</strong>'s
<a href="https://github.com/6to5/grunt-6to5">repo</a> for more info. If you
find any bugs please
<a href="https://github.com/6to5/grunt-6to5/issues">report them</a>.
</p>
<p>
<em>Issues with the output should be reported on the 6to5
<a href="https://github.com/6to5/6to5/issues">issue tracker</a></em>.
</p>
</blockquote>
**Install**
```sh
$ npm install --save-dev grunt-6to5
```
**Usage**
```js
require('load-grunt-tasks')(grunt); // npm install --save-dev load-grunt-tasks
grunt.initConfig({
'6to5': {
options: {
sourceMap: true
},
dist: {
files: {
'dist/app.js': 'src/app.js'
}
}
}
});
grunt.registerTask('default', ['6to5']);
```
### Gulp
<blockquote class="to5-callout to5-callout-info">
<p>
See <strong>gulp-6to5</strong>'s
<a href="https://github.com/6to5/gulp-6to5">repo</a> for more info. If you
find any bugs please
<a href="https://github.com/6to5/gulp-6to5/issues">report them</a>.
</p>
<p>
<em>Issues with the output should be reported on the 6to5
<a href="https://github.com/6to5/6to5/issues">issue tracker</a></em>.
</p>
</blockquote>
**Install**
```sh
$ npm install --save-dev gulp-6to5
```
**Usage**
```js
var gulp = require('gulp');
var to5 = require('gulp-6to5');
gulp.task('default', function () {
return gulp.src('src/app.js')
.pipe(to5())
.pipe(gulp.dest('dist'));
});
```
**Source maps**
Use [gulp-sourcemaps](https://github.com/floridoo/gulp-sourcemaps) like this:
```js
var gulp = require('gulp');
var sourcemaps = require('gulp-sourcemaps');
var to5 = require('gulp-6to5');
var concat = require('gulp-concat');
gulp.task('default', function () {
return gulp.src('src/**/*.js')
.pipe(sourcemaps.init())
.pipe(to5())
.pipe(concat('all.js'))
.pipe(sourcemaps.write('.'))
.pipe(gulp.dest('dist'));
});
```
### Webpack
<blockquote class="to5-callout to5-callout-info">
<p>
See <strong>6to5-loader</strong>'s
<a href="https://github.com/6to5/6to5-loader">repo</a> for more info. If you
find any bugs please
<a href="https://github.com/6to5/6to5-loader/issues">report them</a>.
</p>
<p>
<em>Issues with the output should be reported on the 6to5
<a href="https://github.com/6to5/6to5/issues">issue tracker</a></em>.
</p>
</blockquote>
**Install**
```sh
$ npm install --save-dev 6to5-loader
```
**Usage via loader**
```js
import Animal from '6to5!./Animal.js';
class Person extends Animal {
constructor(arg='default') {
this.eat = 'Happy Meal';
}
}
export default Person;
```
```js
var Person = require('6to5!./Person.js').default;
new Person();
```
**Usage via config**
```js
module: {
loaders: [
{ test: /\.js$/, exclude: /node_modules/, loader: '6to5-loader'}
]
}
```
and then import normally:
```js
import Person from './Person.js';
```
<blockquote class="to5-callout to5-callout-warning">
<h4>Troubleshooting</h4>
<p>
For additional information on how to troubleshoot **6to5-loader** please
see the
<a href="https://github.com/6to5/6to5-loader#troubleshooting">README</a>.
</p>
</blockquote>
## Misc
### Connect
<blockquote class="to5-callout to5-callout-info">
<p>
See <strong>6to5-connect</strong>'s
<a href="https://github.com/6to5/6to5-connect">repo</a> for more info. If
you find any bugs please
<a href="https://github.com/6to5/6to5-connect/issues">report them</a>.
</p>
<p>
<em>Issues with the output should be reported on the 6to5
<a href="https://github.com/6to5/6to5/issues">issue tracker</a></em>.
</p>
</blockquote>
**Install**
```js
$ npm install 6to5-connect
```
**Usage**
```js
var to5Middleware = require('6to5-connect');
app.use(to5Middleware({
options: {
// options to use when transforming files
},
src: 'assets',
dest: 'cache'
}));
app.use(connect.static('cache'));
```
### Jade
<blockquote class="to5-callout to5-callout-info">
<p>
See <strong>jade-6to5</strong>'s
<a href="https://github.com/6to5/jade-6to5">repo</a> for more info. If you
find any bugs please
<a href="https://github.com/6to5/jade-6to5/issues">report them</a>.
</p>
<p>
<em>Issues with the output should be reported on the 6to5
<a href="https://github.com/6to5/6to5/issues">issue tracker</a></em>.
</p>
</blockquote>
**Install**
```js
$ npm install jade-6to5
```
**Usage**
```js
var jade = require('jade');
var to5 = require('jade-6to5');
jade.filters.to5 = to5({});
```
OR
```js
var jade = require('jade');
var to5 = require('jade-6to5');
jade = to5({}, jade);
```
Now you can use ES6 in your jade templates as following.
```jade
script
:to5
console.log('Hello World !!!');
class Person {
constructor(name) {
this.name = name;
}
sayName(){
console.log(`Hello, my name is ${this.name}`);
}
}
var person = new Person('Apoxx');
person.sayName();
```
### Jest
<blockquote class="to5-callout to5-callout-info">
<p>
See <strong>6to5-jest</strong>'s
<a href="https://github.com/6to5/6to5-jest">repo</a> for more info. If you
find any bugs please
<a href="https://github.com/6to5/6to5-jest/issues">report them</a>.
</p>
<p>
<em>Issues with the output should be reported on the 6to5
<a href="https://github.com/6to5/6to5/issues">issue tracker</a></em>.
</p>
</blockquote>
**Install**
```sh
$ npm install --save-dev 6to5-jest
```
**Usage**
In your `package.json` file please make the following changes:
```
{
"dependencies": {
"6to5-jest": "*",
"jest": "*"
},
"scripts": {
"test": "jest"
},
"jest": {
"scriptPreprocessor": "<rootDir>/node_modules/6to5-jest",
"testFileExtensions": ["es6", "js"],
"moduleFileExtensions": ["js", "json", "es6"]
}
}
```
### Karma
<blockquote class="to5-callout to5-callout-info">
<p>
See <strong>karma-6to5-preprocessor</strong>'s
<a href="https://github.com/6to5/karma-6to5-preprocessor">repo</a> for more
info. If you find any bugs please
<a href="https://github.com/6to5/karma-6to5-preprocessor/issues">report them</a>.
</p>
<p>
<em>Issues with the output should be reported on the 6to5
<a href="https://github.com/6to5/6to5/issues">issue tracker</a></em>.
</p>
</blockquote>
**Install**
```js
npm install --save-dev karma-6to5-preprocessor
```
**Usage**
See 6to5 options for more details.
Given `options` properties are passed to 6to5 with no change except:
- `filename`
- `sourceMapName`
- `sourceFileName`
Because they should differ from file to file, corresponding configuration
functions are available.
For example, inline sourcemap configuration would look like the following.
```js
module.exports = function(config) {
config.set({
files: [
'src/**/*.js',
'test/**/*.js'
],
preprocessors: {
'src/**/*.js': ['6to5'],
'test/**/*.js': ['6to5']
},
'6to5Preprocessor': {
options: {
sourceMap: 'inline'
},
filename: function(file) {
return file.originalPath.replace(/\.js$/, '.es5.js');
},
sourceFileName: function(file) {
return file.originalPath;
}
}
});
};
```
### Mocha
<blockquote class="to5-callout to5-callout-info">
<p>
See <strong>6to5-mocha</strong>'s
<a href="https://github.com/6to5/6to5-mocha">repo</a> for more info. If you
find any bugs please
<a href="https://github.com/6to5/6to5-mocha/issues">report them</a>.
</p>
<p>
<em>Issues with the output should be reported on the 6to5
<a href="https://github.com/6to5/6to5/issues">issue tracker</a></em>.
</p>
</blockquote>
**Install**
```sh
$ npm install --save-dev 6to5
```
**Usage**
```js
{
"scripts": {
"test": "mocha --require 6to5/register"
},
"devDependencies": {
"6to5": "*",
"mocha": "*"
}
}
```

771
doc/tour.md Normal file
View File

@ -0,0 +1,771 @@
---
layout: docs
title: Tour
description: A detailed overview of ECMAScript 6 features.
permalink: /docs/tour/
redirect_from: /features.html
---
<blockquote class="to5-callout to5-callout-info">
<h4>es6features</h4>
<p>
This document is taken from Luke Hoban's excellent
<a href="http://git.io/es6features">es6features</a> repo. Go give it a star
on GitHub!
</p>
</blockquote>
<blockquote class="to5-callout to5-callout-info">
<h4>REPL</h4>
<p>
Be sure to try these features out in the online
<a href="repl.html">REPL</a>.
</p>
</blockquote>
## Introduction
> ECMAScript 6 is the upcoming version of the ECMAScript standard. This
standard is targeting ratification in June 2015. ES6 is a significant update to
the language, and the first update to the language since ES5 was standardized in
2009. Implementation of these features in major JavaScript engines is
[underway now](http://kangax.github.io/es5-compat-table/es6/).
See the [draft ES6 standard](https://people.mozilla.org/~jorendorff/es6-draft.html)
for full specification of the ECMAScript 6 language.
## ECMAScript 6 Features
### Arrows
Arrows are a function shorthand using the `=>` syntax. They are syntactically
similar to the related feature in C#, Java 8 and CoffeeScript. They support
both expression and statement bodies. Unlike functions, arrows share the same
lexical `this` as their surrounding code.
```js
// Expression bodies
var odds = evens.map(v => v + 1);
var nums = evens.map((v, i) => v + i);
// Statement bodies
nums.forEach(v => {
if (v % 5 === 0)
fives.push(v);
});
// Lexical this
var bob = {
_name: "Bob",
_friends: [],
printFriends() {
this._friends.forEach(f =>
console.log(this._name + " knows " + f));
}
}
```
### Classes
ES6 classes are a simple sugar over the prototype-based OO pattern. Having a
single convenient declarative form makes class patterns easier to use, and
encourages interoperability. Classes support prototype-based inheritance, super
calls, instance and static methods and constructors.
```js
class SkinnedMesh extends THREE.Mesh {
constructor(geometry, materials) {
super(geometry, materials);
this.idMatrix = SkinnedMesh.defaultMatrix();
this.bones = [];
this.boneMatrices = [];
//...
}
update(camera) {
//...
super.update();
}
static defaultMatrix() {
return new THREE.Matrix4();
}
}
```
### Enhanced Object Literals
Object literals are extended to support setting the prototype at construction,
shorthand for `foo: foo` assignments, defining methods and making super calls.
Together, these also bring object literals and class declarations closer
together, and let object-based design benefit from some of the same
conveniences.
```js
var obj = {
// __proto__
__proto__: theProtoObj,
// Shorthand for handler: handler
handler,
// Methods
toString() {
// Super calls
return "d " + super.toString();
},
// Computed (dynamic) property names
[ 'prop_' + (() => 42)() ]: 42
};
```
<blockquote class="to5-callout to5-callout-warning">
<p>
<code>__proto__</code> support comes from the JavaScript engine running
your program. Although most support the now standard property,
<a href="http://kangax.github.io/compat-table/es6/#__proto___in_object_literals">some do not</a>.
</p>
</blockquote>
### Template Strings
Template strings provide syntactic sugar for constructing strings. This is
similar to string interpolation features in Perl, Python and more. Optionally, a
tag can be added to allow the string construction to be customized, avoiding
injection attacks or constructing higher level data structures from string
contents.
```js
// Basic literal string creation
`In JavaScript '\n' is a line-feed.`
// Multiline strings
`In JavaScript this is
not legal.`
// Construct a DOM query
var name = "Bob", time = "today";
`Hello ${name}, how are you ${time}?`
// Construct an HTTP request prefix is used to interpret the replacements and construction
GET`http://foo.org/bar?a=${a}&b=${b}
Content-Type: application/json
X-Credentials: ${credentials}
{ "foo": ${foo},
"bar": ${bar}}`(myOnReadyStateChangeHandler);
```
### Destructuring
Destructuring allows binding using pattern matching, with support for matching
arrays and objects. Destructuring is fail-soft, similar to standard object
lookup `foo["bar"]`, producing `undefined` values when not found.
```js
// list matching
var [a, , b] = [1,2,3];
// object matching
var { op: a, lhs: { op: b }, rhs: c }
= getASTNode()
// object matching shorthand
// binds `op`, `lhs` and `rhs` in scope
var {op, lhs, rhs} = getASTNode()
// Can be used in parameter position
function g({name: x}) {
console.log(x);
}
g({name: 5})
// Fail-soft destructuring
var [a] = [];
a === undefined;
// Fail-soft destructuring with defaults
var [a = 1] = [];
a === 1;
```
### Default + Rest + Spread
Callee-evaluated default parameter values. Turn an array into consecutive
arguments in a function call. Bind trailing parameters to an array. Rest
replaces the need for `arguments` and addresses common cases more directly.
```js
function f(x, y=12) {
// y is 12 if not passed (or passed as undefined)
return x + y;
}
f(3) == 15
```
```js
function f(x, ...y) {
// y is an Array
return x * y.length;
}
f(3, "hello", true) == 6
```
```js
function f(x, y, z) {
return x + y + z;
}
// Pass each elem of array as argument
f(...[1,2,3]) == 6
```
### Let + Const
Block-scoped binding constructs. `let` is the new `var`. `const` is
single-assignment. Static restrictions prevent use before assignment.
```js
function f() {
{
let x;
{
// okay, block scoped name
const x = "sneaky";
// error, const
x = "foo";
}
// error, already declared in block
let x = "inner";
}
}
```
### Iterators + For..Of
Iterator objects enable custom iteration like CLR IEnumerable or Java
Iteratable. Generalize `for..in` to custom iterator-based iteration with
`for..of`. Dont require realizing an array, enabling lazy design patterns like
LINQ.
```js
let fibonacci = {
[Symbol.iterator]() {
let pre = 0, cur = 1;
return {
next() {
[pre, cur] = [cur, pre + cur];
return { done: false, value: cur }
}
}
}
}
for (var n of fibonacci) {
// truncate the sequence at 1000
if (n > 1000)
break;
print(n);
}
```
Iteration is based on these duck-typed interfaces (using
[TypeScript](http://typescriptlang.org) type syntax for exposition only):
```ts
interface IteratorResult {
done: boolean;
value: any;
}
interface Iterator {
next(): IteratorResult;
}
interface Iterable {
[Symbol.iterator](): Iterator
}
```
### Generators
Generators simplify iterator-authoring using `function*` and `yield`. A function
declared as function* returns a Generator instance. Generators are subtypes of
iterators which include additional `next` and `throw`. These enable values to
flow back into the generator, so `yield` is an expression form which returns a
value (or throws).
Note: Can also be used to enable await-like async programming, see also ES7
`await` proposal.
```js
var fibonacci = {
[Symbol.iterator]: function*() {
var pre = 0, cur = 1;
for (;;) {
var temp = pre;
pre = cur;
cur += temp;
yield cur;
}
}
}
for (var n of fibonacci) {
// truncate the sequence at 1000
if (n > 1000)
break;
print(n);
}
```
The generator interface is (using [TypeScript](http://typescriptlang.org) type
syntax for exposition only):
```ts
interface Generator extends Iterator {
next(value?: any): IteratorResult;
throw(exception: any);
}
```
### Comprehensions
Array and generator comprehensions provide simple declarative list processing
similar as used in many functional programming patterns.
```js
// Array comprehensions
var results = [
for(c of customers)
if (c.city == "Seattle")
{ name: c.name, age: c.age }
]
// Generator comprehensions
var results = (
for(c of customers)
if (c.city == "Seattle")
{ name: c.name, age: c.age }
)
```
### Unicode
Non-breaking additions to support full Unicode, including new unicode literal
form in strings and new RegExp `u` mode to handle code points, as well as new
APIs to process strings at the 21bit code points level. These additions support
building global apps in JavaScript.
```js
// same as ES5.1
"𠮷".length == 2
// new RegExp behaviour, opt-in u
"𠮷".match(/./u)[0].length == 2
// new form
"\u{20BB7}"=="𠮷" == "\uD842\uDFB7"
// new String ops
"𠮷".codePointAt(0) == 0x20BB7
// for-of iterates code points
for(var c of "𠮷") {
console.log(c);
}
```
### Modules
Language-level support for modules for component definition. Codifies patterns
from popular JavaScript module loaders (AMD, CommonJS). Runtime behaviour
defined by a host-defined default loader. Implicitly async model no code
executes until requested modules are available and processed.
```js
// lib/math.js
export function sum(x, y) {
return x + y;
}
export var pi = 3.141593;
```
```js
// app.js
module math from "lib/math";
alert("2π = " + math.sum(math.pi, math.pi));
```
```js
// otherApp.js
import {sum, pi} from "lib/math";
alert("2π = " + sum(pi, pi));
```
Some additional features include `export default` and `export *`:
```js
// lib/mathplusplus.js
export * from "lib/math";
export var e = 2.71828182846;
export default function(x) {
return Math.exp(x);
}
```
```js
// app.js
module math from "lib/mathplusplus";
import exp from "lib/mathplusplus";
alert("2π = " + exp(math.pi, math.e));
```
<blockquote class="to5-callout to5-callout-info">
<h4>Module Formatters</h4>
<p>
6to5 can transpile ES6 Modules to several different formats including
Common.js, AMD, System, and UMD. You can even create your own. For more
details see the <a href="modules.html">modules docs</a>.
</p>
</blockquote>
### Module Loaders
Module loaders support:
- Dynamic loading
- State isolation
- Global namespace isolation
- Compilation hooks
- Nested virtualization
The default module loader can be configured, and new loaders can be constructed
to evaluated and load code in isolated or constrained contexts.
```js
// Dynamic loading System is default loader
System.import('lib/math').then(function(m) {
alert("2π = " + m.sum(m.pi, m.pi));
});
// Create execution sandboxes new Loaders
var loader = new Loader({
global: fixup(window) // replace console.log
});
loader.eval("console.log('hello world!');");
// Directly manipulate module cache
System.get('jquery');
System.set('jquery', Module({$: $})); // WARNING: not yet finalized
```
<blockquote class="to5-callout to5-callout-warning">
<h4>Additional polyfill needed</h4>
<p>
Since 6to5 defaults to using common.js modules, it does not include the
polyfill for the module loader api. Get it
<a href="https://github.com/ModuleLoader/es6-module-loader">here</a>.
</p>
</blockquote>
<blockquote class="to5-callout to5-callout-info">
<h4>Using Module Loader</h4>
<p>
In order to use this, you'll need to tell 6to5 to use the
<code>system</code> module formatter. Also be sure to check out
<a href="https://github.com/systemjs/systemjs">System.js</a>
</p>
</blockquote>
### Map + Set + WeakMap + WeakSet
Efficient data structures for common algorithms. WeakMaps provides leak-free
object-keyd side tables.
```js
// Sets
var s = new Set();
s.add("hello").add("goodbye").add("hello");
s.size === 2;
s.has("hello") === true;
// Maps
var m = new Map();
m.set("hello", 42);
m.set(s, 34);
m.get(s) == 34;
// Weak Maps
var wm = new WeakMap();
wm.set(s, { extra: 42 });
wm.size === undefined
// Weak Sets
var ws = new WeakSet();
ws.add({ data: 42 });
// Because the added object has no other references, it will not be held in the set
```
<blockquote class="to5-callout to5-callout-info">
<h4>Support via polyfill</h4>
<p>
In order to support Promises you must include the 6to5 Polyfill.
</p>
</blockquote>
### Proxies
Proxies enable creation of objects with the full range of behaviors available to
host objects. Can be used for interception, object virtualization,
logging/profiling, etc.
```js
// Proxying a normal object
var target = {};
var handler = {
get: function (receiver, name) {
return `Hello, ${name}!`;
}
};
var p = new Proxy(target, handler);
p.world === 'Hello, world!';
```
```js
// Proxying a function object
var target = function () { return 'I am the target'; };
var handler = {
apply: function (receiver, ...args) {
return 'I am the proxy';
}
};
var p = new Proxy(target, handler);
p() === 'I am the proxy';
```
There are traps available for all of the runtime-level meta-operations:
```js
var handler =
{
get:...,
set:...,
has:...,
deleteProperty:...,
apply:...,
construct:...,
getOwnPropertyDescriptor:...,
defineProperty:...,
getPrototypeOf:...,
setPrototypeOf:...,
enumerate:...,
ownKeys:...,
preventExtensions:...,
isExtensible:...
}
```
<blockquote class="to5-callout to5-callout-danger">
<h4>Unsupported feature</h4>
<p>
Due to the limitations of ES5, Proxies cannot be transpiled or polyfilled.
See support from various
<a href="http://kangax.github.io/compat-table/es6/#Proxy">JavaScript
engines</a>.
</p>
</blockquote>
### Symbols
Symbols enable access control for object state. Symbols allow properties to be
keyed by either `string` (as in ES5) or `symbol`. Symbols are a new primitive
type. Optional `name` parameter used in debugging - but is not part of identity.
Symbols are unique (like gensym), but not private since they are exposed via
reflection features like `Object.getOwnPropertySymbols`.
```js
(function() {
// module scoped symbol
var key = Symbol("key");
function MyClass(privateData) {
this[key] = privateData;
}
MyClass.prototype = {
doStuff: function() {
... this[key] ...
}
};
})();
var c = new MyClass("hello")
c["key"] === undefined
```
<blockquote class="to5-callout to5-callout-info">
<h4>Support via polyfill</h4>
<p>
In order to support Promises you must include the 6to5 Polyfill.
</p>
</blockquote>
### Subclassable Built-ins
In ES6, built-ins like `Array`, `Date` and DOM `Element`s can be subclassed.
Object construction for a function named `Ctor` now uses two-phases (both
virtually dispatched):
- Call `Ctor[@@create]` to allocate the object, installing any special behavior
- Invoke constructor on new instance to initialize
The known `@@create` symbol is available via `Symbol.create`. Built-ins now
expose their `@@create` explicitly.
```js
// Pseudo-code of Array
class Array {
constructor(...args) { /* ... */ }
static [Symbol.create]() {
// Install special [[DefineOwnProperty]]
// to magically update 'length'
}
}
// User code of Array subclass
class MyArray extends Array {
constructor(...args) { super(...args); }
}
// Two-phase 'new':
// 1) Call @@create to allocate object
// 2) Invoke constructor on new instance
var arr = new MyArray();
arr[1] = 12;
arr.length == 2
```
### Math + Number + String + Object APIs
Many new library additions, including core Math libraries, Array conversion
helpers, and Object.assign for copying.
```js
Number.EPSILON
Number.isInteger(Infinity) // false
Number.isNaN("NaN") // false
Math.acosh(3) // 1.762747174039086
Math.hypot(3, 4) // 5
Math.imul(Math.pow(2, 32) - 1, Math.pow(2, 32) - 2) // 2
"abcde".contains("cd") // true
"abc".repeat(3) // "abcabcabc"
Array.from(document.querySelectorAll('*')) // Returns a real Array
Array.of(1, 2, 3) // Similar to new Array(...), but without special one-arg behavior
[0, 0, 0].fill(7, 1) // [0,7,7]
[1,2,3].findIndex(x => x == 2) // 1
["a", "b", "c"].entries() // iterator [0, "a"], [1,"b"], [2,"c"]
["a", "b", "c"].keys() // iterator 0, 1, 2
["a", "b", "c"].values() // iterator "a", "b", "c"
Object.assign(Point, { origin: new Point(0,0) })
```
<blockquote class="to5-callout to5-callout-warning">
<h4>Limited support from polyfill</h4>
<p>
Most of these APIs are supported by the 6to5 Polyfill. However, certain
features are omitted for various reasons (ie.
<code>String.prototype.normalize</code> needs a lot of additional code to
support). You can find more polyfills
<a href="https://github.com/addyosmani/es6-tools#polyfills">here</a>.
</p>
</blockquote>
### Binary and Octal Literals
Two new numeric literal forms are added for binary (`b`) and octal (`o`).
```js
0b111110111 === 503 // true
0o767 === 503 // true
```
<blockquote class="to5-callout to5-callout-warning">
<h4>Only supports literal form</h4>
<p>
6to5 is only able to transform <code>0o767</code> and not
<code>Number('0o767')</code>.
</p>
</blockquote>
### Promises
Promises are a library for asynchronous programming. Promises are a first class
representation of a value that may be made available in the future. Promises are
used in many existing JavaScript libraries.
```js
function timeout(duration = 0) {
return new Promise((resolve, reject) => {
setTimeout(resolve, duration);
})
}
var p = timeout(1000).then(() => {
return timeout(2000);
}).then(() => {
throw new Error("hmm");
}).catch(err => {
return Promise.all([timeout(100), timeout(200)]);
})
```
<blockquote class="to5-callout to5-callout-info">
<h4>Support via polyfill</h4>
<p>
In order to support Promises you must include the 6to5 Polyfill.
</p>
</blockquote>
### Reflect API
Full reflection API exposing the runtime-level meta-operations on objects. This
is effectively the inverse of the Proxy API, and allows making calls
corresponding to the same meta-operations as the proxy traps. Especially useful
for implementing proxies.
```js
// No sample yet
```
<blockquote class="to5-callout to5-callout-danger">
<h4>Limited support from polyfill</h4>
<p>
Core.js only currently supports <code>Reflect.ownKeys</code>, if you would
like a much more complete Reflect API, include another polyfill such as
<a href="https://github.com/tvcutsem/harmony-reflect">Harmony Reflect</a>.
</p>
</blockquote>
### Tail Calls
Calls in tail-position are guaranteed to not grow the stack unboundedly. Makes
recursive algorithms safe in the face of unbounded inputs.
```js
function factorial(n, acc = 1) {
'use strict';
if (n <= 1) return acc;
return factorial(n - 1, n * acc);
}
// Stack overflow in most implementations today,
// but safe on arbitrary inputs in eS6
factorial(100000)
```
<blockquote class="to5-callout to5-callout-danger">
<h4>Unsupported feature</h4>
<p>
Due to high complexity of transpiling Tail Calls, 6to5 does not currently
have them implemented. See
<a href="https://github.com/6to5/6to5/issues/256">#256</a>.
</p>
</blockquote>

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@ -1,259 +0,0 @@
# Usage
## CLI
Compile the file `script.js` and output it to stdout.
```sh
$ 6to5 script.js
```
Compile the file `script.js` and output it to `script-compiled.js`.
```sh
$ 6to5 script.js --out-file script-compiled.js
```
Compile the file `script.js` and output it to `script-compiled.js` and save a
source map to `script-compiled.js.map`.
```sh
$ 6to5 script.js --source-maps --out-file script-compiled.js
```
Compile the file `script.js` and output it to `script-compiled.js` with a source
map embedded in a comment at the bottom.
```sh
$ 6to5 script.js --source-maps-inline --out-file script-compiled.js
```
Compile the entire `src` directory and output it to the `lib` directory.
```sh
$ 6to5 src --out-dir lib
```
Compile the entire `src` directory and output it to the one concatenated file.
```sh
$ 6to5 src --out-file script-compiled.js
```
Pipe a file in via stdin and output it to `script-compiled.js`
```sh
$ 6to5 --out-file script-compiled.js < script.js
```
### Node
Launch a repl.
```sh
$ 6to5-node
```
Evaluate code.
```sh
$ 6to5-node -e "class Test { }"
```
Compile and run `test.js`.
```sh
$ 6to5-node test
```
## Node
```javascript
var to5 = require("6to5");
```
### to5.transform(code, [opts]);
```javascript
var result = to5.transform("code();", options);
result.code;
result.map;
result.ast;
```
### to5.transformFileSync(filename, [opts])
```javascript
to5.transformFileSync("filename.js", options).code;
```
### to5.transformFile(filename, [opts], callback)
```javascript
to5.transformFile("filename.js", options, function (err, result) {
result.code;
});
```
### to5.transform.fromAst(ast, [code], [opts])
```javascript
var result = to5.transform.fromAst(ast, "var a = 2;", opts);
result.code;
result.map;
result.ast;
```
#### Options
```javascript
{
// Filename for use in errors etc.
// Default: "unknown"
filename: "filename",
// Filename relative to `sourceRoot`
// Default: `filename` option.
filenameRelative: "",
// List of transformers to EXCLUDE.
// Run `6to5 --help` to see a full list of transformers.
blacklist: [],
// List of transformers to ONLY use.
// Run `6to5 --help` to see a full list of transformers.
whitelist: [],
// Module formatter to use
// Run `6to5 --help` to see a full list of module formatters.
// Default: "common"
modules: "common",
// If truthy, adds a `map` property to returned output.
// If set to "inline", a comment with a sourceMappingURL directive is added to
// the bottom of the returned code.
// Default: false
sourceMap: true,
// Set `file` on returned source map.
// Default: `filenameRelative` option.
sourceMapName: "filename",
// Set `sources[0]` on returned source map.
// Default: `filenameRelative` option.
sourceFileName: "filename",
// The root from which all sources are relative
// Default: `moduleRoot` option.
sourceRoot: "assets/scripts",
// Optional prefix for the AMD module formatter that will be prepend to the
// filename on module definitions
// Default: `sourceRoot` option.
moduleRoot: "my-app",
// If truthy, insert an explicit id for each defined AMD/System module.
// By default, AMD/System modules are anonymous.
// Default: false
moduleIds: true,
// Optionally replace all 6to5 helper declarations with a referenece to this
// variable. If set to `true` then the default namespace is used "to5Runtime".
// Default: false
runtime: true,
// Enable support for experimental ES7 features
// Default: false
experimental: true,
// Set this to `false` if you don't want the transformed AST in the returned
// result
// Default: true
ast: true,
// Set this to `false` if you don't want the transformed code in the returned
// result
// Default: true
code: true,
format: {
// Output comments in generated output
// Default: true
comments: true,
// Do not include superfluous whitespace characters and line terminators
// Default: false
compact: false,
indent: {
// Preserve parentheses in new expressions that have no arguments
// Default: true
parentheses: true,
// Adjust the indentation of multiline comments to keep asterisks vertically aligned
// Default: true
adjustMultilineComment: true,
// Indent string
// Default: " "
style: " ",
// Base indent level
// Default: 0
base: 0
}
}
}
```
### Require hook
All subsequent files required by node with the extensions `.es6`, `.es` and `.js` will
be transformed by 6to5. The polyfill specified in [Polyfill](polyfill.md) is
also required; but this is automatically loaded when using:
Source maps are automatically configured so if any errors a thrown then line
number info is mapped and you'll get the correct source location.
```javascript
require("6to5/register");
```
**NOTE:** By default all requires to `node_modules` will be ignored. You can
override this by passing an ignore regex via:
```javascript
require("6to5/register")({
// This will override `node_modules` ignoring - you can alternatively pass
// a regex
ignore: false
});
```
**NOTE:** Using 6to5-node or `require("6to5/register")`, 6to5 will check what features are available in the current environment and blacklists them if they're supported.
#### Options
```javascript
require("6to5/register")({
// Optional ignore regex - if any filenames **do** match this regex then they
// aren't compiled
ignore: /regex/,
// Optional only regex - if any filenames **don't** match this regex then they
// aren't compiled
only: /my_es6_folder/,
// See options above for usage
whitelist: [],
blacklist: [],
// This will remove the currently hooked extensions of .es6 and .js so you'll
// have to add them back if you want them to be used again.
extensions: [".js", ".es6"],
// Enables `roadrunner` cache that will save to a `.roadrunner.json` file in your cwd
// Do not check this into git as it's user-specific
cache: true
});
```

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---
layout: docs
title: API
description: How to use the Node.js API.
permalink: /docs/usage/api/
---
```javascript
var to5 = require('6to5');
```
## to5.transform
Transforms the passed in `code`.
```
to5.transform(code, [options])
```
**Example**
```js
var result = to5.transform('code();', options);
result.code;
result.map;
result.ast;
```
## to5.transformFile
Asynchronously transforms the entire contents of a file.
```js
to5.transformFile(filename, [options], callback)
```
**Example**
```js
to5.transformFile('filename.js', options, function (err, result) {
result.code;
});
```
## to5.transformFileSync
Synchronous version of `to5.transformFile`. Returns the transformed contents of
the `filename`.
```js
to5.transformFileSync(filename, [options])
```
**Example**
```js
to5.transformFileSync('filename.js', options).code;
```

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---
layout: docs
title: Browser
description: How to transpile in the browser.
permalink: /docs/usage/browser/
redirect_from: /browser.html
---
<p class="lead">
A browser version of 6to5 is available from `browser.js` inside the 6to5
directory in an npm release.
</p>
<blockquote class="to5-callout to5-callout-warning">
<h4>Not intended for serious use</h4>
<p>
Compiling in the browser has a fairly limited use case, so if you are
working on a production site you should be precompiling your scripts
server-side. See <a href="../setup/#build-systems">setup build systems</a>
for more information.
</p>
</blockquote>
## Script tags
When the `browser.js` file is included all scripts with the type
`text/ecmascript-6` and `text/6to5` are automatically compiled and ran.
```html
<script src="node_modules/6to5/browser.js"></script>
<script type="text/6to5">
class Test {
test() {
return 'test';
}
}
var test = new Test;
test.test(); // "test"
</script>
```
## API
Programmatically transpile and execute strings of ES6 code.
See [options](#options) for additional documentation.
### `to5.transform(code, [opts])`
```js
to5.transform('class Test {}').code;
```
### `to5.run(code, [opts])`
````js
to5.run('class Test {}');
````

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---
layout: docs
title: CLI
description: How to use the CLI tools.
permalink: /docs/usage/cli/
redirect_from: /usage.html
---
<p class="lead">
6to5 comes with a built-in CLI which can be used to compile files from the
command line.
</p>
## Install
Using [npm](https://www.npmjs.com/) you can install 6to5 globally, making it
available from the command line.
```sh
$ npm install --global 6to5
```
## 6to5
#### Compile Files
Compile the file `script.js` and **output to stdout**.
```sh
$ 6to5 script.js
# output...
```
If you would like to **output to a file** you may use `--out-file` or `-o`.
```sh
$ 6to5 script.js --out-file script-compiled.js
```
### Compile with Source Maps
If you would then like to add a **source map file** you can use
`--source-maps` or `-s`. [Learn more about source maps](http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/).
```sh
$ 6to5 script.js --out-file script-compiled.js --source-maps
```
If you would rather have **inline source maps**, you may use
`--source-maps-inline` or `-t`.
```sh
$ 6to5 script.js --out-file script-compiled.js --source-maps-inline
```
### Compile Directories
Compile the entire `src` directory and output it to the `lib` directory.
```sh
$ 6to5 src --out-dir lib
```
Compile the entire `src` directory and output it to the one concatenated file.
```sh
$ 6to5 src --out-file script-compiled.js
```
### Piping Files
Pipe a file in via stdin and output it to `script-compiled.js`
```sh
$ 6to5 --out-file script-compiled.js < script.js
```
## 6to5-node
6to5 comes with a second CLI which works exactly the same as Node.js's CLI, only
it will compile ES6 code before running it.
Launch a REPL (Read-Eval-Print-Loop).
```sh
$ 6to5-node
```
Evaluate code.
```sh
$ 6to5-node -e "class Test { }"
```
Compile and run `test.js`.
```sh
$ 6to5-node test
```

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---
layout: docs
title: Experimental
description: How to use experimental ES7 features.
permalink: /docs/usage/experimental/
redirect_from: /experimental.html
---
> 6to5 also has experimental support for ES7 proposals.
<blockquote class="to5-callout to5-callout-danger">
<h4>Subject to change</h4>
<p>
These proposals are subject to change so <strong><em>use with extreme
caution</em></strong>. 6to5 may update without warning in order to track spec
changes. Please do not use them in production applications.
</p>
</blockquote>
#### Usage
```js
$ 6to5 --experimental
```
```js
to5.transform('code', { experimental: true });
```

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---
layout: docs
title: JSX
description: How to use JSX.
permalink: /docs/usage/jsx/
---
<p class="lead">
6to5 has built-in support for React v0.12. Tags are automatically transformed
to their equivalent <code>React.createElement(...)</code> and
<code>displayName</code> is automatically inferred and added to all
<code>React.createClass</code> calls.
</p>
## Blacklist
To disable this behaviour add react to your blacklist:
````js
to5.transform("code", { blacklist: ["react"] });
$ 6to5 --blacklist react
```

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@ -1,37 +1,39 @@
# Modules
---
layout: docs
title: Modules
description: How to use module formatters.
permalink: /docs/usage/modules/
redirect_from: /modules.html
---
<p class="lead">
6to5 has the ability to transpile ES6 modules to the module system of your
choice. You can even easily create your own.
</p>
## Usage
### CLI
```sh
$ 6to5 --modules common script.js
```
### Node
```javascript
var to5 = require("6to5");
```js
to5.transform('import "foo";', { modules: "common" });
```
## Formats
* [AMD](#amd)
* [Common (Default)](#common-default)
* [Ignore](#ignore)
* [System](#system)
* [UMD](#umd)
### Common (Default)
### Common
**Usage**
```sh
$ 6to5 --modules common
```
**In**
**Example**
```javascript
```js
export default test;
export {test};
@ -46,9 +48,7 @@ import {bar} from "foo";
import {foo as bar} from "foo";
```
**Out**
```javascript
```js
"use strict";
var _interopRequire = function (obj) {
@ -72,13 +72,15 @@ var bar = require("foo").foo;
### AMD
**Usage**
```sh
$ 6to5 --modules amd
```
**In**
**Example**
```javascript
```js
import foo from "foo";
export function bar() {
@ -86,9 +88,7 @@ export function bar() {
}
```
**Out**
```javascript
```js
define(["exports", "foo"], function (exports, _foo) {
"use strict";
@ -105,21 +105,24 @@ define(["exports", "foo"], function (exports, _foo) {
});
```
You can optionally specify to include the module id (using the `--amd-module-id` argument):
You can optionally specify to include the module id (using the `--amd-module-id`
argument):
```javascript
```js
define("filename", ["exports", "foo"], function (exports, _foo) {})
```
### UMD
### System
**Usage**
```sh
$ 6to5 --modules umd
$ 6to5 --modules system
```
**In**
**Example**
```javascript
```js
import foo from "foo";
export function bar() {
@ -127,9 +130,46 @@ export function bar() {
}
```
**Out**
```js
System.register("bar", ["foo"], function (_export) {
"use strict";
```javascript
var __moduleName = "bar";
var foo;
function bar() {
return foo("foobar");
}
return {
setters: [function (m) {
foo = m.default;
}],
execute: function () {
_export("bar", bar);
}
};
});
```
### UMD
**Usage**
```sh
$ 6to5 --modules umd
```
**Example**
```js
import foo from "foo";
export function bar() {
return foo("foobar");
}
```
```js
(function (factory) {
if (typeof define === "function" && define.amd) {
define(["exports", "foo"], factory);
@ -154,13 +194,15 @@ export function bar() {
### Ignore
**Usage**
```sh
$ 6to5 --modules ignore
```
**In**
**Example**
```javascript
```js
import foo from "foo";
export function bar() {
@ -168,69 +210,30 @@ export function bar() {
}
```
**Out**
```javascript
```js
function bar() {
return foo("foobar");
}
```
### System
```sh
$ 6to5 --modules system
```
**In**
```javascript
import foo from "foo";
export function bar() {
return foo("foobar");
}
```
**Out**
```javascript
System.register("bar", ["foo"], function (_export) {
"use strict";
var __moduleName = "bar";
var foo;
function bar() {
return foo("foobar");
}
return {
setters: [function (m) {
foo = m.default;
}],
execute: function () {
_export("bar", bar);
}
};
});
```
## Custom
### Custom
You can alternatively specify module names instead of one of the built-in types.
```sh
**Usage**
```js
$ 6to5 --modules custom-module-formatter
```
**node_modules/custom-module-formatter/index.js**
**Example**
```javascript
**`node_modules/custom-module-formatter/index.js`**
```js
module.exports = ModuleFormatter;
function ModuleFormatter() {
}
function ModuleFormatter() {}
ModuleFormatter.prototype.transform = function (ast) {
// this is ran after all transformers have had their turn at modifying the ast

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@ -0,0 +1,35 @@
---
layout: docs
title: Options
description: Options for 6to5 transpiling.
permalink: /docs/usage/options/
---
## Usage
```js
to5.transform(code, options);
```
```sh
$ 6to5 --name=value
```
## Options
| Option | Default | Description |
| ------------------ | -------------------- | ------------------------------- |
| `filename` | `"unknown"` | Filename for use in errors etc. |
| `fileNameRelative` | `(filename)` | Filename relative to `sourceRoot`. |
| `blacklist` | `[]` | Array of transformers to **exclude**. Run `6to5 --help` to see a full list of transformers. |
| `whitelist` | `[]` | Array of transformers to **only** use. Run `6to5 --help` to see a full list of transformers. |
| `modules` | `"common"` | Which module formatter to use. Run `6to5 --help` to see a full list of module formatters. |
| `sourceMap` | `false` | If truthy, adds a `map` property to returned output. If set to `"inline"`, a comment with a sourceMappingURL directive is added to the bottom of the returned code. |
| `sourceMapName` | `(filenameRelative)` | Set `file` on returned source map. |
| `sourceFileName` | `(filenameRelative)` | Set `sources[0]` on returned source map. |
| `sourceRoot` | `(moduleRoot)` | The root from which all sources are relative. |
| `moduleRoot` | `(sourceRoot)` | Optional prefix for the AMD module formatter that will be prepend to the filename on module definitions. |
| `amdModuleIds` | `false` | If truthy, insert an explicit id for each defined AMD module. By default, AMD modules are anonymous. |
| `runtime` | `false` | Optionally replace all 6to5 helper declarations with a referenece to this variable. If set to `true` then the default namespace is used `to5Runtime`. |
| `comments` | `true` | Output comments in generated output. |
| `experimental` | `false` | Enable support for experimental ES7 features. |

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---
layout: docs
title: Playground
description: How to use the playground.
permalink: /docs/usage/playground/
redirect_from: /playground.html
---
> Playground is a proving ground for language ideas.
<blockquote class="to5-callout to5-callout-danger">
<h4>Unofficial</h4>
<p>
These features are in no way endorsed by Ecma International and are not a
part of any ECMAScript standard, nor are they necessarily on track to become
part of any standard. <strong><em>Use with extreme caution</em></strong>.
</p>
</blockquote>
<blockquote class="to5-callout to5-callout-info">
<h4>Proposal Authors</h4>
<p>
If you are actively working on an
<a href="https://github.com/tc39/ecma262">ECMAScript proposal</a>, this is a
good place to get your ideas implemented with so that they may be tested
with all of the latest language and API features.
</p>
<p>
Please feel free to <a href="https://github.com/6to5/6to5/issues/new">open
an issue</a> on the 6to5 repository with your WIP spec, and we can discuss
getting it implemented. Be sure to include as much information as possible.
</p>
</blockquote>
## Usage
```js
$ 6to5 --playground
```
```js
to5.transform('code', { playground: true });
```
<blockquote class="to5-callout to5-callout-info">
<h4>Enables experimental</h4>
<p>
Enabling playground also enables experimental support.
</p>
</blockquote>
## Features
### Memoization assignment operator
The memoization assignment operator allows you to lazily set an object property.
It checks whether there's a property defined on the object and if there isn't
then the right hand value is set.
This means that `obj.x` in the following `var x = { x: undefined }; obj.x ?= 2;``
will still be `undefined` because it's already been defined on the object.
**Uses**
```js
var obj = {};
obj.x ?= 2;
obj.x; // 2
obj = { x: 1 };
obj.x ?= 2;
obj.x; // 1
obj = { x: undefined }
obj.x ?= 2;
obj.x; // undefined
```
**Example**
```js
var obj = {};
obj.x ?= 2;
```
is equivalent to
```js
var obj = {};
if (!Object.prototype.hasOwnProperty.call(obj, 'x')) obj.x = 2;
```
### Method binding
```javascript
var fn = obj#method;
var fn = obj#method("foob");
```
is equivalent to
```javascript
var fn = obj.method.bind(obj);
var fn = obj.method.bind(obj, "foob");
```
### Method binding function shorthand
```javascript
["foo", "bar"].map(#toUpperCase); // ["FOO", "BAR"]
[1.1234, 23.53245, 3].map(#toFixed(2)); // ["1.12", "23.53", "3.00"]
```
equivalent to
```javascript
["foo", "bar"].map(function (val) { return val.toUpperCase(); });
[1.1234, 23.53245, 3].map(function (val) { return val.toFixed(2); });
```
### Object getter memoization
```js
var foo = {
memo bar() {
return complex();
}
};
class Foo {
memo bar() {
return complex();
}
}
```
is equivalent to
```js
var foo = {
get bar() {
return Object.defineProperty(this, "bar", {
value: complex(),
enumerable: true,
configurable: true,
writable: true
}).bar;
}
};
class Foo {
get bar() {
return Object.defineProperty(this, "bar", {
value: complex(),
enumerable: true,
configurable: true,
writable: true
}).bar;
}
}
```
### This shorthand
```js
@foo
```
is equivalent to
```
this.foo
```

56
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@ -0,0 +1,56 @@
---
layout: docs
title: Polyfill
description: How to use the Polyfill.
permalink: /docs/usage/polyfill/
---
<p class="lead">
6to5 includes a polyfill that includes a custom
<a href="https://github.com/facebook/regenerator/blob/master/runtime.js">regenerator runtime</a>
and <a href="https://github.com/zloirock/core-js">core.js</a>.
</p>
This will emulate a full ES6 environment. This polyfill is automatically loaded
when using `6to5-node` and `6to5/register`.
## Usage in Node/Browserify
You need to include the polyfill require at the top the **entry point** to
your application.
```js
require('6to5/polyfill');
```
Fortunately, this is automatically loaded when using:
```js
require('6to5/register');
```
## Usage in Browser
Available from the `browser-polyfill.js` file within the 6to5 directory of an
npm release. This needs to be included **before** all your compiled 6to5 code.
You can either prepend it to your compiled code or include it in a `<script>`
before it.
**NOTE:** Do not `require` this via browserify etc, use `6to5/polyfill`.
<blockquote class="to5-callout to5-callout-warning">
<h4>Polyfills are not perfect</h4>
<p>
Due to limitations in various ES5 environments not every polyfill will work
in every environment.
</p>
</blockquote>
<blockquote class="to5-callout to5-callout-warning">
<h4>Certain polyfills not included</h4>
<p>
Certain polyfills are too large/complex for their implemented features to
justify including them for all builds. You may have to include additional
polyfills for a subset of ES6 features.
</p>
</blockquote>

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@ -0,0 +1,55 @@
---
layout: docs
title: Require Hook
description: How to use the require hook.
permalink: /docs/usage/require/
---
## Install
```sh
$ npm install 6to5
```
## Usage
```js
require('6to5/register');
```
All subsequent files required by node with the extensions `.es6`, `.es`, and
`.js` will be transformed by 6to5. The polyfill specified in Polyfill is also
required.
**NOTE:** By default all requires to `node_modules` will be ignored. You can
override this by passing an ignore regex via:
```js
require('6to5/register')({
// This will override `node_modules` ignoring - you can alternatively pass
// a regex
ignore: false
});
```
## Register Options
```javascript
require('6to5/register')({
// Optional ignore regex - if any filenames **do** match this regex then they
// aren't compiled
ignore: /regex/,
// Optional only regex - if any filenames **don't** match this regex then they
// aren't compiled
only: /my_es6_folder/,
// See options above for usage
whitelist: [],
blacklist: [],
// This will remove the currently hooked extensions of .es6 and .js so you'll
// have to add them back if you want them to be used again.
extensions: ['.js', '.es6']
});
```

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@ -1,4 +1,11 @@
# Optional runtime
---
layout: docs
title: Optional Runtime
description: How to use the optional runtime.
permalink: /docs/usage/runtime/
---
## Details
6to5 has a few helper functions that'll be placed at the top of the generated
code if needed so it's not inlined multiple times throughout that file. This may
@ -8,25 +15,17 @@ to the browser. gzip alleviates most of this concern but it's still not ideal.
You can tell 6to5 to not place any declarations at the top of your files and
instead just point them to a reference contained within the runtime.
Simply use the following option if you're using the [Node API](usage.md#node):
## Usage
```javascript
{
runtime: true
}
```
or the following flag if you're using the [CLI](usage.md#cli):
```ssh
```js
$ 6to5 --runtime
```
Then just include the runtime before your generated code.
```js
to5.transform('code', { runtime: true });
```
## Getting the runtime
You can get the runtime via either:
### Getting the runtime
```sh
$ 6to5-runtime
@ -34,24 +33,24 @@ $ 6to5-runtime
or
```javascript
require("6to5").runtime();
```js
require('6to5').runtime();
```
or from an npm release in `runtime.js` from the 6to5 directory.
## Customising namespace
### Customising namespace
You can also customise the runtime namespace by passing an optional namespace
argument:
```javascript
require("6to5").runtime("myCustomNamespace");
```
```sh
$ 6to5-runtime myCustomNamespace
```
See [Options - runtime](usage.md#options) for documentation on changing the
reference in generated code.
```js
require("6to5").runtime('myCustomNamespace');
```
See [Options - runtime](../options) for documentation on changing the reference in
generated code.