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ESLint

ESLint

ESLint is a linter for JavaScript, JSON and TypeScript.

You can enable the ESLint linter with:

trunk check enable eslint

Auto Enabling

ESLint will be auto-enabled if any of its config files are present: eslint.config.js, eslint.config.mjs, eslint.config.cjs.

Settings

ESLint supports the following config files:

  • eslint.config.js

  • eslint.config.mjs

  • eslint.config.cjs

  • .eslintrc

  • .eslintrc.cjs

  • .eslintrc.js

  • .eslintrc.json

  • .eslintrc.mjs

  • .eslintrc.yaml

  • .eslintrc.yml

Unlike with most tools under trunk check, these files cannot be moved.

Usage Notes

ESLint >= 9.x

As of ESLint v9, all of the formatters have been removed. We suggest using prettier to format Javascript and Typescript code. The extra package mentioned below is no longer needed for ESLint v9 and higher.

ESlint < 8.x

Most ESLint users use several plugins, custom parsers, etc. Trunk has turned off sandboxing and caching for ESLint so it can use your repo's installed packages for ESLint plugins, and other required ESLint packages. Trunk controls the ESLint version, but otherwise, ESLint looks for all plugins, configs, etc. based on the path of the source file it is linting. This all means you do need to have npm/yarn installed in your repo as a prerequisite before running ESLint via trunk.

We recommend you disable all Prettier rules in your ESLint config and let Trunk run Prettier automatically on your files. It's much nicer to just autoformat a file than to see a lint error for every missing space.

You can easily do this by:

  • adding the eslint-config-prettier package

  • adding prettier as the last element to the extends property in your ESLint config

For example, your extends list might look like:

extends:
  # Order matters, later configs purposefully override settings from earlier configs
  - eslint:recommended
  - airbnb
  - plugin:@typescript-eslint/recommended
  - plugin:import/recommended
  - plugin:import/typescript
  - plugin:node/recommended
  - plugin:mocha/recommended
  - plugin:react/recommended
  - prettier # this actually turns OFF all Prettier rules running via ESLint

Links

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