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:tropical_fish: Babel is a compiler for writing next generation JavaScript.


The compiler for writing next generation JavaScript.

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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.


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


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

Try it out at our REPL%3B&experimental=true&loose=true&spec=false&playground=false&stage=0) and follow us at @babeljs.



Check out our website:

Looking for support?

For questions and support please visit our discussion forum, sign up for our Slack community, or StackOverflow.

Want to report a bug or request a feature?

Bugs and feature requests can be posted at

We’ve moved our issues from phabricator back to github issues!

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

Want to report an issue with (the website)?

For documentation and website issues please visit the babel/ repo.

Want to contribute to Babel?

Check out our If you have already joined slack, join our #development channel!

You can also start by checking out the issues with the help-wanted label.

Our discussions/notes/roadmap: babel/notes


The Babel repo is managed as a monorepo; it’s composed of many npm packages.

Core Packages

Package Version Dependencies
babel-core npm Dependency Status
babylon npm Dependency Status
babel-traverse npm Dependency Status
babel-generator npm Dependency Status

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 (moved to a separate repo and versioned independently) - The transformer[s]: All the plugins/presets - These all use babel-traverse to traverse through the AST - The generator: babel-generator

The flow goes like this:

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

Check out the babel-handbook for more information on this.


Package Version Dependencies
babel-cli npm Dependency Status
babel-types npm Dependency Status
babel-polyfill npm Dependency Status
babel-runtime npm Dependency Status
babel-register npm Dependency Status
babel-template npm Dependency Status
babel-helpers npm Dependency Status
babel-code-frame npm Dependency Status
  • 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.
  • babel-types is used to validate, build, change AST nodes.
  • babel-polyfill is literally a wrapper around core-js and regenerator-runtime. Check out the docs.
  • 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 (usually in library/plugin code). Check out the docs.
  • babel-register is a way to automatically compile files with babel on the fly by binding to node’s require. Check out the docs.
  • 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 is a set of premade babel-template functions that are used in some babel plugins.
  • babel-code-frame is a standalone package used to generate errors that prints the source code and points to error locations.


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 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 npm Dependency Status automatically determines plugins and polyfills you need based on your supported environments

You can find community maintained presets on npm


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

You can find community plugins on npm.

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.

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.


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


Core members

Babel | Daniel Tschinder | Logan Smyth | Henry Zhu | |—|—|—|—| Babel | Daniel Tschinder | Logan Smyth | Henry Zhu | :octocat: @babel | @danez | @loganfsmyth | @hzoo | :bird: @babeljs | @TschinderDaniel | @loganfsmyth | @left_pad |


Andrew Levine Boopathi Rajaa Brian Ng Dan Harper diogo franco Aaron Ang Artem Yavorsky
Andrew Levine Boopathi Rajaa Brian Ng Dan Harper Diogo Franco Aaron Ang Artem Yavorsky
@drewml @boopathi @existentialism @danharper @kovensky @aaronang @yavorsky
@drewml @heisenbugger @existentialism @DanHarper7 @kovnsk @_aaronang @yavorsky_
Juriy Zaytsev Kai Cataldo Moti Zilberman Sven Sauleau Samuel Reed Sergey Rubanov
Juriy Zaytsev Kai Cataldo Moti Zilberman Sven Sauleau Samuel Reed Sergey Rubanov
@kangax @kaicataldo @motiz88 @xtuc @STRML @chicoxyzzy
@kangax @kai_cataldo @motiz88 @svensauleau @STRML_ @chicoxyzzy

Non-Human Members

| |—| | Babel Bot | | @babel-bot | | @babeljs |

Inactive members

Amjad Masad | James Kyle | Jesse McCarthy | Sebastian McKenzie (Creator) | |—|—|—|—| Amjad Masad | James Kyle | Jesse McCarthy | Sebastian McKenzie | @amasad | @thejameskyle | @jmm | @sebmck | | @amasad | @thejameskyle | @mccjm | @kittens


Support us with a monthly donation and help us continue our activities. [Become a backer]


Become a sponsor and get your logo on our README on Github with a link to your site. [Become a sponsor]



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Top Contributors

kittens hzoo amasad thejameskyle loganfsmyth jmm eventualbuddha neVERberleRfellerER RReverser webpro danez gaearon AluisioASG sindresorhus samwgoldman kpdecker zloirock lydell guybedford benjamn monsanto samccone vhf gzzhanghao AgentME zertosh jridgewell josh phantom10111 ForbesLindesay


package version
dev async ^1.5.0
babel-cli 7.0.0-alpha.18
babel-core 7.0.0-alpha.18
babel-eslint 8.0.0-alpha.15
babel-plugin-istanbul ^4.1.4
babel-preset-env 2.0.0-alpha.18
babel-preset-flow 7.0.0-alpha.18
babel-preset-stage-0 7.0.0-alpha.18
babel-register 7.0.0-alpha.18
browserify ^13.1.1
bundle-collapser ^1.2.1
chai ^4.1.0
chalk ^2.0.0
derequire ^2.0.2
eslint ^3.14.1
eslint-config-babel ^7.0.1
eslint-plugin-flowtype ^2.20.0
eslint-plugin-prettier ^2.1.2
flow-bin ^0.41.0
gulp ^3.9.0
gulp-babel 7.0.0-alpha.18
gulp-newer ^1.0.0
gulp-plumber ^1.0.1
gulp-util ^3.0.7
gulp-watch ^4.3.5
husky ^0.13.2
lerna 2.0.0-rc.4
lerna-changelog ^0.2.0
lint-staged ^3.6.1
lodash ^4.2.0
mocha ^3.0.0
nyc ^11.0.3
output-file-sync ^2.0.0
prettier ^1.5.0
rimraf ^2.4.3
semver ^5.0.0
through2 ^2.0.0
uglify-js ^2.4.16


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