BPScott/jest

Super-fast alternative for babel-jest or ts-jest without type checking

@swc/jest

swc binding for the jest

Installation

# if you use npm
npm i -D jest @swc/core @swc/jest
# if you use yarn
yarn add -D jest @swc/core @swc/jest

Usage

jest.config.js:

module.exports = {
  transform: {
    '^.+\\.(t|j)sx?$': '@swc/jest',
  },
}

It will load swc configuration from .swcrc in default. You also can custom it:

const fs = require('fs')

const config = JSON.parse(fs.readFileSync(`${__dirname}/.swcrc`, 'utf-8'))

module.exports = {
  transform: {
    '^.+\\.(t|j)sx?$': ['@swc/jest', { ...config, /* custom configuration in jest */ }],
  },
}

Q & A

Q: Jest use CommonJS in default. But I want to use ESM.

A: Setup Jest following this Guide.

For JavaScript, it need to configure package.json:

{
  // ...
  "type": "module"
}

For TypeScript, it need some configuration in jest.config.js:

module.exports = {
  // ...
  extensionsToTreatAsEsm: ['.ts', '.tsx'],
}

Run test with --experimental-vm-modules:

cross-env NODE_OPTIONS=--experimental-vm-modules jest

# or
node --experimental-vm-modules ./node_modules/jest/bin/jest.js

License

MIT