<p align="center">
  <a href="https://babeljs.io/">
    <img alt="babel" src="https://raw.githubusercontent.com/babel/logo/master/babel.png" width="546">
  </a>
</p>

<p align="center">
  The compiler for writing next generation JavaScript.
</p>

<p align="center">
  <a href="https://medium.com/friendship-dot-js/i-peeked-into-my-node-modules-directory-and-you-wont-believe-what-happened-next-b89f63d21558"><img alt="Business Strategy Status" src="https://img.shields.io/badge/Business%20Model-flavortown-green.svg"></a>
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</p>

Babel is a community-driven tool that helps you write the latest version of JavaScript.

When your supported environments don't support certain features natively, it will help you compile it down to a supported version.

**In**

```js
// ES2015 arrow function
[1, 2, 3].map((n) => n + 1);
```

**Out**

```js
[1, 2, 3].map(function(n) {
  return n + 1;
});
```

Try it out at our [REPL](https://babeljs.io/repl/#?babili=false&evaluate=true&lineWrap=false&presets=latest&code=%5B1%2C2%2C3%5D.map(n%20%3D%3E%20n%20%2B%201)%3B&experimental=true&loose=true&spec=false&playground=false&stage=0) and follow us at [@babeljs](https://twitter.com/babeljs).

- [FAQ](#faq)
- [Packages](#packages)
  - [Core Packages](#core-packages)
  - [Other](#other) 
  - [Presets](#presets)
  - [Plugins](#plugins)
    - [Transform Plugins](#transform-plugins)
    - [Syntax Plugins](#syntax-plugins)
  - [Misc Packages](#misc-packages)
- [Team](#team)
- [License](#license)

# FAQ

## Docs?

Check out our website: [babeljs.io](http://babeljs.io/)

## Looking for support?

For questions and support please visit our [discussion forum](https://discuss.babeljs.io/), sign up for our [Slack community](https://slack.babeljs.io/), or [StackOverflow](http://stackoverflow.com/questions/tagged/babeljs).

## Want to report a bug or request a feature?

Bugs and feature requests can be posted at https://github.com/babel/babel/issues.

> We've moved our issues from phabricator back to github issues!

Former phabricator issue urls now automatically redirect to their corresponding Github issue:

https://phabricator.babeljs.io/T2168 mostly corresponds to https://github.com/babel/babel/issues/2168.

## Want to report an issue with [babeljs.io](https://babeljs.io) (the website)?

For documentation and website issues please visit the [babel/babel.github.io](https://github.com/babel/babel.github.io) repo.

## Want to contribute to Babel?

Check out our [CONTRIBUTING.md](https://github.com/babel/babel/blob/master/CONTRIBUTING.md). If you have already joined slack, join our [#development](https://babeljs.slack.com/messages/development) channel!

You can also start by checking out the issues with the [help-wanted](https://github.com/babel/babel/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22) label.

Our discussions/notes/roadmap: [babel/notes](https://github.com/babel/notes)

## Packages

The Babel repo is managed as a [monorepo](https://github.com/babel/babel/blob/master/doc/design/monorepo.md); it's composed of many npm packages.

### Core Packages

| Package | Version | Dependencies |
|--------|-------|------------|
| [`babel-core`](/packages/babel-core) | [![npm](https://img.shields.io/npm/v/babel-core.svg?maxAge=2592000)](https://www.npmjs.com/package/babel-core) | [![Dependency Status](https://david-dm.org/babel/babel.svg?path=packages/babel-core)](https://david-dm.org/babel/babel?path=packages/babel-core) |
| [`babylon`](https://github.com/babel/babylon) | [![npm](https://img.shields.io/npm/v/babylon.svg?maxAge=2592000)](https://www.npmjs.com/package/babylon) | [![Dependency Status](https://david-dm.org/babel/babylon.svg)](https://david-dm.org/babel/babylon) |
| [`babel-traverse`](/packages/babel-traverse) | [![npm](https://img.shields.io/npm/v/babel-traverse.svg?maxAge=2592000)](https://www.npmjs.com/package/babel-traverse) | [![Dependency Status](https://david-dm.org/babel/babel.svg?path=packages/babel-traverse)](https://david-dm.org/babel/babel?path=packages/babel-traverse) |
| [`babel-generator`](/packages/babel-generator) | [![npm](https://img.shields.io/npm/v/babel-generator.svg?maxAge=2592000)](https://www.npmjs.com/package/babel-generator) | [![Dependency Status](https://david-dm.org/babel/babel.svg?path=packages/babel-generator)](https://david-dm.org/babel/babel?path=packages/babel-generator) |

[`babel-core`](/packages/babel-core) is the Babel compiler itself; it exposes the `babel.transform` method, where `transformedCode = transform(src).code`.

The compiler can be broken down into 3 parts:
- The parser: [`babylon`](https://github.com/babel/babylon) (moved to a separate repo and versioned independently)
- The transformer[s]: All the plugins/presets
  - These all use [`babel-traverse`](/packages/babel-traverse) to traverse through the AST
- The generator: [`babel-generator`](/packages/babel-generator)

The flow goes like this:

input string -> `babylon` parser -> `AST` -> transformer[s] -> `AST` -> `babel-generator` -> output string

Check out the [`babel-handbook`](https://github.com/thejameskyle/babel-handbook/blob/master/translations/en/plugin-handbook.md#introduction) for more information on this.

#### Other

| Package | Version | Dependencies |
|--------|-------|------------|
| [`babel-cli`](/packages/babel-cli) | [![npm](https://img.shields.io/npm/v/babel-cli.svg?maxAge=2592000)](https://www.npmjs.com/package/babel-cli) | [![Dependency Status](https://david-dm.org/babel/babel.svg?path=packages/babel-cli)](https://david-dm.org/babel/babel?path=packages/babel-cli) |
| [`babel-types`](/packages/babel-types) | [![npm](https://img.shields.io/npm/v/babel-types.svg?maxAge=2592000)](https://www.npmjs.com/package/babel-types) | [![Dependency Status](https://david-dm.org/babel/babel.svg?path=packages/babel-types)](https://david-dm.org/babel/babel?path=packages/babel-types) |
| [`babel-polyfill`](/packages/babel-polyfill) | [![npm](https://img.shields.io/npm/v/babel-polyfill.svg?maxAge=2592000)](https://www.npmjs.com/package/babel-polyfill) | [![Dependency Status](https://david-dm.org/babel/babel.svg?path=packages/babel-polyfill)](https://david-dm.org/babel/babel?path=packages/babel-polyfill) |
| [`babel-runtime`](/packages/babel-runtime) | [![npm](https://img.shields.io/npm/v/babel-runtime.svg?maxAge=2592000)](https://www.npmjs.com/package/babel-runtime) | [![Dependency Status](https://david-dm.org/babel/babel.svg?path=packages/babel-runtime)](https://david-dm.org/babel/babel?path=packages/babel-runtime) |
| [`babel-register`](/packages/babel-register) | [![npm](https://img.shields.io/npm/v/babel-register.svg?maxAge=2592000)](https://www.npmjs.com/package/babel-register) | [![Dependency Status](https://david-dm.org/babel/babel.svg?path=packages/babel-register)](https://david-dm.org/babel/babel?path=packages/babel-register) |
| [`babel-template`](/packages/babel-template) | [![npm](https://img.shields.io/npm/v/babel-template.svg?maxAge=2592000)](https://www.npmjs.com/package/babel-template) | [![Dependency Status](https://david-dm.org/babel/babel.svg?path=packages/babel-template)](https://david-dm.org/babel/babel?path=packages/babel-template) |
| [`babel-helpers`](/packages/babel-helpers) | [![npm](https://img.shields.io/npm/v/babel-helpers.svg?maxAge=2592000)](https://www.npmjs.com/package/babel-helpers) | [![Dependency Status](https://david-dm.org/babel/babel.svg?path=packages/babel-helpers)](https://david-dm.org/babel/babel?path=packages/babel-helpers) |
| [`babel-code-frame`](/packages/babel-code-frame) | [![npm](https://img.shields.io/npm/v/babel-code-frame.svg?maxAge=2592000)](https://www.npmjs.com/package/babel-code-frame) | [![Dependency Status](https://david-dm.org/babel/babel.svg?path=packages/babel-code-frame)](https://david-dm.org/babel/babel?path=packages/babel-code-frame) |

- [`babel-cli`](/packages/babel-cli) is the CLI tool that runs `babel-core` and helps with outputting to a directory, a file, stdout and more (also includes `babel-node`). Check out the [docs](https://babeljs.io/docs/usage/cli/).
- [`babel-types`](/packages/babel-types) is used to validate, build, change AST nodes.
- [`babel-polyfill`](/packages/babel-polyfill) is [literally a wrapper](https://github.com/babel/babel/blob/master/packages/babel-polyfill/src/index.js) around [`core-js`](https://github.com/zloirock/core-js) and [regenerator-runtime](https://github.com/facebook/regenerator/tree/master/packages/regenerator-runtime). Check out the [docs](https://babeljs.io/docs/usage/polyfill/).
- [`babel-runtime`](/packages/babel-runtime) is similar to the polyfill except that it doesn't modify the global scope and is to be used with [`babel-plugin-transform-runtime`](/packages/babel-plugin-transform-runtime) (usually in library/plugin code). Check out the [docs](https://babeljs.io/docs/plugins/transform-runtime/).
- [`babel-register`](/packages/babel-register) is a way to automatically compile files with babel on the fly by binding to node's require. Check out the [docs](http://babeljs.io/docs/usage/require/).
- [`babel-template`](/packages/babel-template) is a helper function to make AST nodes. Instead you can pass a string representing the code you want to create rather than tediously building them using `babel-types`.
- [`babel-helpers`](/packages/babel-helpers) is a set of premade `babel-template` functions that are used in some babel plugins.
- [`babel-code-frame`](/packages/babel-code-frame) is a standalone package used to generate errors that prints the source code and points to error locations.

### [Presets](http://babeljs.io/docs/plugins/#presets)

After Babel 6, the default transforms were removed; if you don't specify any plugins/presets it will just return the original source code.

The transformer[s] used in Babel are the independent pieces of code that transform specific things. For example: the [`es2015-arrow-functions`](/packages/babel-plugin-transform-es2015-arrow-functions) transform specifically changes arrow functions into a regular function. Presets are just simply an array of plugins that make it easier to run a whole a set of transforms without specifying each one manually.

| Package | Version | Dependencies | Description |
|--------|-------|------------|---|
| [`babel-preset-env`](https://github.com/babel/babel-preset-env) | [![npm](https://img.shields.io/npm/v/babel-preset-env.svg?maxAge=2592000)](https://www.npmjs.com/package/babel-preset-env) | [![Dependency Status](https://david-dm.org/babel/babel-preset-env.svg)](https://david-dm.org/babel/babel-preset-env) | automatically determines plugins and polyfills you need based on your supported environments |

> You can find community maintained presets on [npm](https://www.npmjs.com/search?q=babel-preset)

### [Plugins](http://babeljs.io/docs/plugins)

Plugins are the heart of Babel and what make it work.

> You can find community plugins on [npm](https://www.npmjs.com/search?q=babel-plugin).

#### Transform Plugins

There are many kinds of plugins: ones that convert ES6/ES2015 to ES5, transform to ES3, minification, JSX, flow, experimental features, and more. Check out our [website for more](http://babeljs.io/docs/plugins/#transform-plugins).

#### Syntax Plugins

These just enable the transform plugins to be able to parse certain features (the transform plugins already include the syntax plugins so you don't need both): `babel-plugin-syntax-x`. Check out our [website for more](http://babeljs.io/docs/plugins/#syntax-plugins).

### Helpers

These are mostly for internal use in various plugins: `babel-helper-x`.

## Team

### Core members

[![Babel](https://avatars.githubusercontent.com/u/9637642?s=64)](https://github.com/babel) | [![Daniel Tschinder](https://avatars.githubusercontent.com/u/231804?s=64)](https://github.com/danez) | [![Logan Smyth](https://avatars.githubusercontent.com/u/132260?s=64)](https://github.com/loganfsmyth) | [![Henry Zhu](https://avatars.githubusercontent.com/u/588473?s=64)](https://github.com/hzoo) | 
|---|---|---|---|
Babel | Daniel Tschinder | Logan Smyth | Henry Zhu |
:octocat: [@babel](https://github.com/babel) | [@danez](https://github.com/danez) | [@loganfsmyth](https://github.com/loganfsmyth) | [@hzoo](https://github.com/hzoo) |
:bird: [@babeljs](https://twitter.com/babeljs) | [@TschinderDaniel](https://twitter.com/TschinderDaniel) | [@loganfsmyth](https://twitter.com/loganfsmyth) | [@left_pad](https://twitter.com/left_pad) |

### Members

[![Andrew Levine](https://avatars.githubusercontent.com/u/5233399?s=64)](https://github.com/drewml) | [![Boopathi Rajaa](https://avatars.githubusercontent.com/u/294474?s=64)](https://github.com/boopathi) | [![Brian Ng](https://avatars.githubusercontent.com/u/56288?s=64)](https://github.com/existentialism) | [![Dan Harper](https://avatars.githubusercontent.com/u/510740?s=64)](https://github.com/danharper) | [![diogo franco](https://avatars.githubusercontent.com/u/73085?s=64)](https://github.com/kovensky) | [![Aaron Ang](https://avatars1.githubusercontent.com/u/7579804?s=64)](https://github.com/aaronang) | [![Artem Yavorsky](https://avatars2.githubusercontent.com/u/1521229?s=64)](https://github.com/yavorsky) |
|---|---|---|---|---|---|---|
| Andrew Levine | Boopathi Rajaa | Brian Ng | Dan Harper | Diogo Franco | Aaron Ang | Artem Yavorsky |
| [@drewml](https://github.com/drewml) | [@boopathi](https://github.com/boopathi) | [@existentialism](https://github.com/existentialism) | [@danharper](https://github.com/danharper) | [@kovensky](https://github.com/kovensky) | [@aaronang](https://github.com/aaronang) | [@yavorsky](https://github.com/yavorsky) |
| [@drewml](https://twitter.com/drewml) | [@heisenbugger](https://twitter.com/heisenbugger) | [@existentialism](https://twitter.com/existentialism) | [@DanHarper7](https://twitter.com/DanHarper7) | [@kovnsk](https://twitter.com/kovnsk) | [@_aaronang](https://twitter.com/_aaronang) | [@yavorsky_](https://twitter.com/yavorsky_) |

[![Juriy Zaytsev](https://avatars.githubusercontent.com/u/383?s=64)](https://github.com/kangax) | [![Kai Cataldo](https://avatars.githubusercontent.com/u/7041728?s=64)](https://github.com/kaicataldo) | [![Moti Zilberman](https://avatars.githubusercontent.com/u/2246565?s=64)](https://github.com/motiz88) | [![Sven Sauleau](https://avatars3.githubusercontent.com/u/1493671?s=64)](https://github.com/xtuc) | [![Samuel Reed](https://avatars3.githubusercontent.com/u/1197375?s=64)](https://github.com/STRML) | [![Sergey Rubanov](https://avatars1.githubusercontent.com/u/1507086?s=64)](https://github.com/chicoxyzzy) |
|---|---|---|---|---|---|
| Juriy Zaytsev | Kai Cataldo | Moti Zilberman | Sven Sauleau | Samuel Reed | Sergey Rubanov |
| [@kangax](https://github.com/kangax) | [@kaicataldo](https://github.com/kaicataldo) | [@motiz88](https://github.com/motiz88) | [@xtuc](https://github.com/xtuc) | [@STRML](https://github.com/STRML) | [@chicoxyzzy](https://github.com/chicoxyzzy) |
| [@kangax](https://twitter.com/kangax) | [@kai_cataldo](https://twitter.com/kai_cataldo) | [@motiz88](https://twitter.com/motiz88) | [@svensauleau](https://twitter.com/svensauleau) | [@STRML_](https://twitter.com/STRML_) | [@chicoxyzzy](https://twitter.com/chicoxyzzy) |

### Non-Human Members

[<img src="https://github.com/babel/babel-bot/raw/master/babel-bot.png" height="64">](https://github.com/babel-bot) | 
|---|
| Babel Bot |
| [@babel-bot](https://github.com/babel-bot) |
| [@babeljs](https://twitter.com/babeljs) |

### Inactive members

[![Amjad Masad](https://avatars.githubusercontent.com/u/587518?s=64)](https://github.com/amasad) | [![James Kyle](https://avatars.githubusercontent.com/u/952783?s=64)](https://github.com/thejameskyle) | [![Jesse McCarthy](https://avatars.githubusercontent.com/u/129203?s=64)](https://github.com/jmm) | [![Sebastian McKenzie](https://avatars.githubusercontent.com/u/853712?s=64)](https://github.com/kittens) (Creator) | 
|---|---|---|---|
Amjad Masad | James Kyle | Jesse McCarthy | Sebastian McKenzie | 
[@amasad](https://github.com/amasad) | [@thejameskyle](https://github.com/thejameskyle) | [@jmm](https://github.com/jmm) | [@sebmck](https://twitter.com/sebmck) |
| [@amasad](https://twitter.com/amasad) | [@thejameskyle](https://twitter.com/thejameskyle) | [@mccjm](https://twitter.com/mccjm) | [@kittens](https://github.com/kittens) 

## License

[MIT](https://github.com/babel/babel/blob/master/LICENSE)

