@metamask/eslint-config

This package provides MetaMask's ESLint configuration as an extensible shared config.

Usage

We export four ESLint configurations.

Base config

Our default export contains a base set of ESLint rules for ES6+:

yarn add --dev \
    eslint@^6.8.0 \
    eslint-plugin-import@^2.20.1 \
    @metamask/eslint-config@^3.0.0

List @metamask/eslint-config to your ESLint config via extends:

module.exports = {
  extends: [
    '@metamask/eslint-config',
  ],
}

Node.js

An additional config that supports Node.js-specific environments:

module.exports = {
  extends: [
    '@metamask/eslint-config',
    '@metamask/eslint-config/config/nodejs',
  ],
}

To lint the .eslintrc.js file itself, you will need to add this config in addition to the base config.

Jest

An additional config that adds support for Jest:

yarn add --dev \
    eslint@^6.8.0 \
    eslint-plugin-import@^2.20.1 \
    eslint-plugin-jest@^23.6.0 \
    @metamask/eslint-config@^3.0.0

module.exports = {
  root: true,
  extends: [
    '@metamask/eslint-config',
    '@metamask/eslint-config/config/jest',
  ],
}

Mocha

An additional config that adds support for Mocha:

yarn add --dev \
    eslint@^6.8.0 \
    eslint-plugin-import@^2.20.1 \
    eslint-plugin-mocha@^6.2.2 \
    @metamask/eslint-config@^3.0.0

module.exports = {
  root: true,
  extends: [
    '@metamask/eslint-config',
    '@metamask/eslint-config/config/mocha',
  ],
}

If your project has prefer-arrow-callback you will need to disable that and replace it with mocha/prefer-arrow-callback.

TypeScript

An additional config that adds support for TypeScript:

yarn add --dev \
    eslint@^6.8.0 \
    eslint-plugin-import@^2.20.1 \
    @typescript-eslint/eslint-plugin@^2.20.0 \
    @typescript-eslint/parser@^2.17.0 \
    @metamask/eslint-config@^3.0.0

module.exports = {
  root: true,
  extends: [
    '@metamask/eslint-config',
    '@metamask/eslint-config/config/typescript',
  ],
  // If you have JS files for config, etc. you'll need to set their sourceType
  // explicitly as the default sourceType for TS projects is 'module'
  overrides: [{
    files: [
      '.eslintrc.js',
    ],
    parserOptions: {
      sourceType: 'script',
    },
  }],
};

Release & Publishing

The project follows the same release process as the other libraries in the MetaMask organization:

1. Create a release branch
   • For a typical release, this would be based on master
   • To update an older maintained major version, base the release branch on the major version branch (e.g. 1.x)
2. Update the changelog
3. Update version in package.json file (e.g. yarn version --minor --no-git-tag-version)
4. Create a pull request targeting the base branch (e.g. master or 1.x)
5. Code review and QA
6. Once approved, the PR is squashed & merged
7. The commit on the base branch is tagged
8. The tag can be published as needed