3303b079c5
### `@babel/runtime` - Added `@babel/runtime-corejs3` package and `corejs: 3` options to `@babel/plugin-transform-runtime`. - Added support of instance methods, fixes #8928. - Added flag `proposals` (in `corejs: { version: 3, proposals: true }` format) for support all proposals polyfills from `core-js`. - Used separate directories in runtime for `core-js` entry points with proposals and without. - Used `get-iterator-method` helper for getting iterators, fixes #2500. - As a cheap bonus, added support of IE8- (except some cases of `regenerator`). ### `@babel/polyfill` - Should be deprecated in favor of separate usage required features from `core-js` and `regenerator-runtime` with an informative message. ### `@babel/preset-env` - Uses for built-ins data from [`core-js-compat`](https://github.com/zloirock/core-js/tree/master/packages/core-js-compat) instead of `compat-table` since information from `compat-table` [is not enough](https://github.com/zloirock/core-js/tree/master/packages/core-js-compat). - `useBuilIns` now requires direct setting of `corejs` version option, without it will be used `2` by default and shown deprecation warning. - Added support of minor `core-js` versions for simplify updating in the future. - For preventing some order-related problems, polyfills in the both `core-js@3` plugins added on `post` stage in the order of `core-js-compat` data. - Divided plugins and polyfills parts of `preset-env`, instead of 2 internal plugins for adding polyfills, we have 6: usage and entry versions of plugins for `core-js@2`, ### Current state: `core-js@3`, `regenerator-runtime`. - Added support `samsung` target (for Samsung Internet) since `core-js-compat` and `compat-table` now contains mapping for this, fixes #6602. #### `useBuilIns: entry` with `corejs: 3` - No longer transforms `@babel/polyfill`. - Transforms **all possible** `core-js` entry points to import of related modules (based on data from [`core-js-compat`](https://unpkg.com/core-js-compat@3.0.0-beta.15/entries.json)). - Since of this, we no longer need `shippedProposals` / `proposals` flags with `useBuilIns: entry`. - Removes `regenerator-runtime/runtime` import where it's not required. #### `useBuilIns: usage` with `corejs: 3` - In addition to `shippedProposals`, added flag `proposals` (in `corejs: { version: 3, proposals: true }` format) for polyfill all proposals from `core-js`. - Fixed list of dependencies in built-in definitions. - Improved the way of determination method / built-in name and source of this method. - Adds import of required polyfills on `MemberExpression`, `ObjectPattern`, `in` operator. - Adds import of required polyfills on access to global object properties. - Adds import of all required common iterators on all syntax features which use iterators protocol (`for-of`, destructuring, spread, `yield` delegation, etc.). - Adds import of promises on syntax features which use promises (async functions/generators, dynamic import, etc.), fixes #9250, #7402, etc. ### `core-js@2` stuff I didn't want to tough `core-js@2`-related stuff, however - Fixed some serious errors in definitions which breaks `Object.getOwnPropertySymbols`, `Symbol.toStringTag` logic, `Promise#finally`, `Array#forEach`, etc. - `Array#flatMap` and trim methods moved to stable features as a part of ES2019 and loaded by deprecated `@babel/polyfill` and `@babel/preset-env` with `corejs: 2` option.
The compiler for writing next generation JavaScript.
Supporting Babel
Babel (pronounced "babble") is a community-driven project used by many companies and projects, and is maintained by a group of volunteers. If you'd like to help support the future of the project, please consider:
- Giving developer time on the project. (Message us on Twitter or Slack for guidance!)
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Bronze
Intro
Babel is a tool that helps you write code in the latest version of JavaScript. When your supported environments don't support certain features natively, Babel will help you compile those features down to a supported version.
In
// ES2015 arrow function
[1, 2, 3].map((n) => n + 1);
Out
[1, 2, 3].map(function(n) {
return n + 1;
});
Try it out at our REPL.
FAQ
Who maintains Babel?
Mostly a handful of volunteers, funded by you! Please check out our team page!
Looking for support?
For questions and support please join our Slack Community (you can sign-up here for an invite), ask a question on Stack Overflow, or ping us on Twitter.
Is there a Babel song?
I'm so glad you asked: Hallelujah —— In Praise of Babel by @angus-c, audio version by @swyx. Tweet us your recordings!
Where are the docs?
Check out our website: babeljs.io, and report issues/features at babel/website.
Want to report a bug or request a feature?
Please read through our CONTRIBUTING.md and fill out the issue template at babel/issues!
Want to contribute to Babel?
Check out our CONTRIBUTING.md to get started with setting up the repo.
- If you have already joined Slack, join our #development channel and say hi!
- Check out the issues with the good first issue and help wanted label. We suggest also looking at the closed ones to get a sense of the kinds of issues you can tackle.
- Our discussions/notes/roadmap: babel/notes
- Our progress on TC39 proposals: babel/proposals
How is the repo structured?
The Babel repo is managed as a monorepo that is composed of many npm packages.