swc/README.md
강동윤 b1e4122b02
Nullish coalescing / optional chaining / comments (#529)
swc_ecma_ast:
 - rename `TsOptChain` to `OptChainExpr` (Fixes #525)
 - add `BinOp::NullishCoalescing`

swc_ecma_parser:
 - parse `??` (Fixes #526)

swc_ecma_transforms:
 - remap comments from fixer (Fixes #528)
2019-12-24 17:01:32 +09:00

6.4 KiB

babel

Make the web (development) faster.

npm Downloads undefined

Travis Status Coverage

Supporting swc

Backers on Open Collective Sponsors on Open Collective

swc is a community-driven project, 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 Slack for guidance!)
  • Giving funds by becoming a sponsor (see below)! Slackin for swc

Open Collective Sponsors

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

Gold Sponsors

Silver Sponsors

Bronze Sponsors

Backers

Become a backer and get your image on our README on Github with a link to your site.

Documentation

Check out the documentation in the website.

Features

Parsers

  • es2019
  • jsx
  • typescript

Transforms

New generation javascript to old-days javascript.

  • es3

    • member-expression-literals
    • property-literals
    • reserved-words
  • es5

    • property-mutators
  • es2015

    • arrow-functions
    • block-scoped-functions
    • block-scoping
    • classes
    • computed-properties
    • destructuring
    • duplicate-keys
    • for-of
    • function-name
    • instanceof
    • literals
    • new-target
    • object-super
    • parameters
    • shorthand-properties
    • spread
    • sticky regex (y flag)
    • template-literals
      • invalid escape sequences inside tagged template literals. (aka es2018)
    • typeof-symbol
    • unicode-regex
  • es2016

    • exponentiation-operator
  • es2017

    • async-to-generator
  • es2018

    • async-generator-functions
    • dotall-regex
    • object-rest-spread
      • Using symbol as a key
    • optional-catch-binding
    • unicode-property-regex
  • es2019 (stage 4)

  • optional catch binding

  • big int literal

  • stage 3

  • class fields

  • numeric separator

  • nullish coalescing

  • stage 2

  • decorators

  • react

    • jsx

Performance

The lower bound of the speedup compared to babel is 18. The benchmarks were run on Macbook pro, dual core, 2.3GHz Intel Core i5, 16 GB ram

performance
swc (es3) 761 ops/sec ±0.23% (89 runs sampled)
swc (es2015) 800 ops/sec ±1.02% (87 runs sampled)
swc (es2016) 2,123 ops/sec ±0.84% (88 runs sampled)
swc (es2017) 2,131 ops/sec ±1.13% (90 runs sampled)
swc (es2018) 2,981 ops/sec ±0.25% (90 runs sampled)
swc-optimize (es3) 712 ops/sec ±0.21% (86 runs sampled)
babel 41.75 ops/sec ±8.07% (56 runs sampled)

Contributing

See CONTRIBUTING.md. You may also find the architecture documentation useful (ARCHITECTURE.md).

License

swc is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0).

See LICENSE-APACHE and LICENSE-MIT for details.