@metamask/eslint-config

This monorepo contains MetaMask's ESLint configurations as npm packages. The different configs are split up into individual packages so that we can correctly specify their peer dependencies.

Contributing

Setup

• Install the current LTS version of Node.js
  • If you are using nvm (recommended) running nvm install will install the latest version and running nvm use will automatically choose the right node version for you.
• Install Yarn v3
• Run yarn install to install dependencies and run any required post-install scripts

Testing and Linting

Run yarn lint to run the linter, or run yarn lint:fix to run the linter and fix any automatically fixable issues.

Updating or Adding Configs

Configs targeting an entirely new environment should be added in a new package. Our rule validation script (see ./scripts/validate-rules.js) forbids the following rules:

• Rules that override Prettier's recommended ESLint rules
• Uselessly configured rules, meaning:
  • Rules that are disabled but never enabled by an extended config.
  • Rules that are configured identically by the package's extended configs.
• For the purpose of determining the "usefulness" of rules, we include our base config (@metamask/eslint-config) in the set of extended configs, since it should always be extended by the consumer in practice.

Linting will fail in CI if any of the above conditions are violated in any config.

Finally, in order to understand the impact of changing rules or the set of extended configs, each package has a rules-snapshot.json fill which contains all rules of the particular config and its extended configs in a single dictionary. When editing a package, always check its rules snapshots after running yarn lint:fix to understand which rules changed.

Release & Publishing

The project follows the same release process as the other libraries in the MetaMask organization. The GitHub Actions action-create-release-pr and action-publish-release are used to automate the release process; see those repositories for more information about how they work.

1. Choose a release version.

2. The release version should be chosen according to SemVer. Analyze the changes to see whether they include any breaking changes, new features, or deprecations, then choose the appropriate SemVer version. See the SemVer specification for more information.

3. If this release is backporting changes onto a previous release, then ensure there is a major version branch for that version (e.g. 1.x for a v1 backport release).

4. The major version branch should be set to the most recent release with that major version. For example, when backporting a v1.0.2 release, you'd want to ensure there was a 1.x branch that was set to the v1.0.1 tag.

5. Trigger the workflow_dispatch event manually for the Create Release Pull Request action to create the release PR.

6. For a backport release, the base branch should be the major version branch that you ensured existed in step 2. For a normal release, the base branch should be the main branch for that repository (which should be the default value).

7. This should trigger the action-create-release-pr workflow to create the release PR.

8. Update the changelog to move each change entry into the appropriate change category (See here for the full list of change categories, and the correct ordering), and edit them to be more easily understood by users of the package.

9. Generally any changes that don't affect consumers of the package (e.g. lockfile changes or development environment changes) are omitted. Exceptions may be made for changes that might be of interest despite not having an effect upon the published package (e.g. major test improvements, security improvements, improved documentation, etc.).

10. Try to explain each change in terms that users of the package would understand (e.g. avoid referencing internal variables/concepts).
11. Consolidate related changes into one change entry if it makes it easier to explain.

12. Run yarn auto-changelog validate --rc to check that the changelog is correctly formatted.

13. Review and QA the release.

14. If changes are made to the base branch, the release branch will need to be updated with these changes and review/QA will need to restart again. As such, it's probably best to avoid merging other PRs into the base branch while review is underway.

15. Squash & Merge the release.

16. This should trigger the action-publish-release workflow to tag the final release commit and publish the release on GitHub.

17. Publish the release on npm.

18. Wait for the publish-release GitHub Action workflow to finish. This should trigger a second job (publish-npm), which will wait for a run approval by the npm publishers team.

19. Approve the publish-npm job (or ask somebody on the npm publishers team to approve it for you).
20. Once the publish-npm job has finished, check npm to verify that it has been published.

Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

Unreleased

14.0.0

Changed

• BREAKING: Bump minimum Node.js version from 16 to 18.18 (#371)
• BREAKING: Bump peer dependency on ESLint from ^8.57.0 to ^9.11.0 (#370)
  • ESLint 9 requires flat configs, so this change also rewrites the configs to use flat configs. The legacy config format is no longer supported.
• BREAKING: Bump peer dependency on @metamask/eslint-config from ^13.0.0 to ^14.0.0 (#377)
• BREAKING: Bump peer dependency on eslint-config-prettier from ^8.5.0 to ^9.1.0 (#370)
• BREAKING: Bump peer dependency on eslint-plugin-import-x from ^0.5.1 to ^4.3.0 (#370)
• BREAKING: Bump peer dependency on eslint-plugin-jsdoc from >=43.0.7 <48 to ^50.2.4 (#370)
• BREAKING: Bump peer dependency on eslint-plugin-prettier from ^4.2.1 to ^5.2.1 (#370)
• BREAKING: Bump peer dependency on eslint-plugin-promise from ^6.1.1 to ^7.1.0 (#370)
• BREAKING: Bump peer dependency on prettier from ^2.7.1 to ^3.3.3 (#370)
• BREAKING: Change package to be pure ESM (#370)
  • ESLint 9 supports ESM out-of-the-box, so this change updates the package to be pure ESM. This means that the package can no longer be used with CommonJS require syntax.

13.0.0

Changed

• BREAKING: Replace eslint-plugin-import with eslint-plugin-import-x (#366)
• BREAKING: Bump all ESLint dependencies (#351)
  • Bumps all ESLint dependencies to the latest version compatible with Node.js 16.
• BREAKING: Bump minimum Node.js version from 14 to 16 (#332, #339)

12.2.0

Changed

• Remove deprecated rule jsdoc/newline-after-description (#290)
  • This means the plugin can now be used with eslint-plugin-jsdoc versions 42 and above.

Fixed

• Pin eslint-plugin-import@~2.26.0 to avoid a regression in eslint-plugin-import@2.27.0 (#307)
• Change endOfLine rules to better support linting on Windows (#311)

12.1.0

Changed

• Add support for typescript 5.0.x, 5.1.x (#288)

12.0.0

Added

• BREAKING: Add eslint-plugin-promise peer dependency, and enable no-multiple-resolved (#287)

11.1.0

Changed

• Exclude test files from package (#266)

11.0.2

Changed

• Stop requiring newlines between multiline blocks/expressions (#263)

11.0.1

Fixed

• Enable function expressions again (#258)
  • We didn't realize this rule would disallow class methods, even class constructors. This was too disruptive.

11.0.0

Added

• BREAKING: Enable id-denylist and id-length in base config (#200)
• BREAKING: Add rules for hybrid Node.js and browser environments (#242)
  • The base config now only allows globals and modules that are available in both Node.js and browsers.
  • This adds a new @metamask/eslint-config-browser package, to be used in browser-only environments.
  • The @metamask/eslint-config-nodejs package has been updated to allow Node.js-only globals and modules.

Changed

• BREAKING: Remove no-undef in favour of custom environments configuration (#254)
• BREAKING: Bump all ESLint dependencies to the latest version (#252)
  • This includes peer dependencies.
• BREAKING: Automatically sort imports (#248)
• BREAKING: Disable more undesired syntax (#207)
  • This disables the with statement, function expressions, and the in operator.

10.0.0

Changed

• BREAKING: Update ESLint from v7 to v8 (#233)
  • This is breaking because eslint is a peerDependency.
  • Four new rules have been added:
    • no-loss-of-precision
    • no-nonoctal-decimal-escape
    • no-unsafe-optional-chaining
    • no-useless-backreference
• BREAKING: Update eslint-plugin-prettier from v3 to v4 (#231)
  • This is breaking beacuse eslint-plugin-prettier is a peerDependency.
• BREAKING: Update minimum Node.js version to v14 (#225)
• Ignore rest siblings for no-unused-vars (#213)
  • This makes the no-unused-vars rule more permissive

9.0.0

Added

• BREAKING: Add JSDoc ESLint rules (#203)

8.0.0

Changed

• BREAKING: Require newlines between multiline blocks and expressions (#197)

7.0.1

Fixed

• Restore default parserOptions (#193)
  • By extending the recommended eslint-plugin-import rules, we accidentally changed the default parserOptions.sourceType to module. The sourceType is now explicitly set to script.
  • In some cases, parserOptions.ecmaVersion could also be set to an incorrect version. The ecmaVersion is now explicitly set to 2017, matching the corresponding setting in env.

7.0.0

Changed

• BREAKING: Update Prettier quoteProps rule to as-needed (#181)
• BREAKING: Update ESLint no-shadow config (#168)
• Use recommended eslint-plugin-import rule sets (#184)
  • This only removed or disabled rules, and is not breaking.
• Update install instructions in readme (#185)
• Normalize rule config values (#169)

6.0.0 - 2021-04-08

Changed

• BREAKING: Set minimum Node.js version to ^12.0.0 (#144)
• BREAKING: Set ECMAScript version to es2017/8 (#150)
• BREAKING: Add the Prettier ESLint plugin and extend the recommended Prettier ESLint config (#96)
  • See here for the eslint-plugin-prettier rules and here for the rules of eslint-config-prettier, which the plugin extends.
  • The rules of this config should otherwise be unchanged.
• Update eslint and other ESLint peer dependencies (#151)

Removed

• BREAKING: All configs except the base config (#141)
  • All configs are now published as separate packages, and must be extended by referencing their package names:
    • @metamask/eslint-config (the base config)
    • @metamask/eslint-config-jest
    • @metamask/eslint-config-mocha
    • @metamask/eslint-config-nodejs
    • @metamask/eslint-config-typescript

5.0.0 - 2021-02-02

Changed

• BREAKING: Enable semi in base config (#101)
• BREAKING: Disallow spaces before parentheses of named functions (#101)
• BREAKING: Upgrade to TypeScript v4 and corresponding @typescript-eslint dependencies (#79, #80, #103)

4.1.0 - 2020-10-21

Changed

• Disable node/no-missing-import (#75)
• Disable node/no-missing-require (#75)

4.0.0 - 2020-10-20

Changed

• BREAKING: Update to ESLint v7 (#46, #58, #62, #63)
• Relax member-delimiter-style for TypeScript (#68)
• Disable space-before-function-paren for TypeScript (#65)

3.2.0 - 2020-08-20

Changed

• Relax prefer-destructuring rules (#57)

3.1.0 - 2020-08-19

Changed

• Disable prefer-object-spread (#54)

3.0.0 - 2020-08-11

Changed

• Disallow all anonymous default exports (#52)
• Set maximum empty lines to 1 (#51)

2.2.0 - 2020-07-14

Changed

• Relax no-plusplus rule (#44)

2.1.1 - 2020-04-17

Changed

• Disable require-await (#37)

2.1.0 - 2020-02-24

Changed

• Disable @typescript-eslint/no-extra-parens (#29)

2.0.0 - 2020-02-20

Added

• Add import rules to base config (#24)
• Clarified TypeScript config & publishing docs

Changed

• Explicitly specify all core rules (#17)
• Update TypeScript config (#25)

Removed

• Remove root flag from TS config (#20)

1.2.0 - 2020-02-18

Changed

• Disable Jest lowercase-name for describe blocks (#14)

1.1.0 - 2020-02-11

Added

• Add README file
• Add Mocha config (#13)

1.0.0 - 2020-01-21

Added

• Add base, TypeScript, and Jest configs (#3)