swc/README.md

speedy web compiler

---

Make the web (development) faster.

swc is rust port of babel and closure compiler.

Installation

Currently this requires nightly version of rust.

npm i -D swc

or

yarn add --dev swc

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
    • Note: this might be buggy (at this time)
  • 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

• react

  • jsx

Performance

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

	performance
swc (ffi)	1,086 ops/sec ±0.77% (84 runs sampled)
swc-optimize (ffi)	1,060 ops/sec ±0.63% (87 runs sampled)
swc (ffi, simd)	1,295 ops/sec ±0.87% (89 runs sampled)
swc-optimize (ffi, simd)	1,270 ops/sec ±0.24% (89 runs sampled)
babel	65.72 ops/sec ±6.45% (62 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.