eslint-config-galex

yarn add -D eslint-config-galex eslint

npm install --save-dev eslint-config-galex eslint

Compatibility

Usage with create-react-app

~~As of January 2021 / due to CRA v5, currently no additional steps are required! 🎉~~

Beginning with eslint-config-galex v4.2.2 or newer, until this disclaimer is removed you need to install the following dependencies additionally:

"eslint-plugin-jest": "27.2.0"

npm i --save-dev eslint-plugin-jest@27.2.0

yarn add -D eslint-plugin-jest@27.2.0

Beginning with eslint-config-galex v4.5.0 or newer, until this disclaimer is removed you need to install the following dependencies additionally:

"eslint-plugin-react": "7.32.2"
"eslint-plugin-jsx-a11y": "6.7.1"
"eslint-plugin-import": "2.27.5"

npm i --save-dev eslint-plugin-react@7.32.2
npm i --save-dev eslint-plugin-jsx-a11y@6.7.1
npm i --save-dev eslint-plugin-import@2.27.5

yarn add -D eslint-plugin-react@7.32.2
yarn add -D eslint-plugin-jsx-a11y@6.7.1
yarn add -D eslint-plugin-import@2.27.5

Usage with Next.js

In your next.config.js, I heavily recommend setting eslint.ignoreDuringBuilds to true. Otherwise, you'll have to install eslint-config-next separately and won't benefit of this config and your customization on top.

Usage with Remix Run

No additional setup is required! 🎉

Setup

Basic

You profit automatically of automatic dependency and feature detection. Due to the nature of ESLint configs however this approach is significantly harder to customize.

// .eslintrc.js
module.exports = {
  extends: 'galex',
};

Advanced

This showcases the required setup to begin with customizing your config on an advanced level. Please check out the Examples section below for more details.

// .eslintrc.js
const { createConfig } = require('eslint-config-galex/dist/createConfig');

module.exports = createConfig();

Features

Incremental Adoption

// .eslintrc.js
const { createConfig } = require('eslint-config-galex/dist/createConfig');

module.exports = createConfig({
  incrementalAdoption: true,
});

Standalone Generation

By default, eslint-config-galex reads your package.json as well as, if present, tsconfig.json to determine feature availability. On weaker machines however, this turned out to be a performance bottleneck. Realistically, neither your dependencies nor your tsconfig change that often.

To generate a static config based on your current dependencies & tsconfig, use:

node node_modules/eslint-config-galex/dist/generateStandalone

which will create a .eslintrc.json in your root directory.

How do I pass settings for createConfig to standalone generation?

Simple! Have a eslint-galex-settings.json file in your root directory and it will be picked up.

An example would look like this:

// eslint-galex-settings.json (remove this comment as its invalid json)
{
  "incrementalAdoption": true
}

Important: to keep this in sync with your dependencies, I recommend adding a postinstall step to your scripts:

// package.json
"scripts": {
  // other scripts
  "postinstall": "node node_modules/eslint-config-galex/dist/generateStandalone"
}

Remember to re-run this command whenever you make feature-availability-relevant changes to your tsconfig.json as well, such as module, target or lib.

History: prior to v4, eslint-config-galex shipped with internal caching. Sadly, this prove to be both a maintenance overhead as well as not as useful as it initially promised to be for various reasons (e.g. VSCode ESLint apparently restarting the process when switching files which cachebusted due to a different process).

Starting with a blank slate

You like all the features eslint-config-galex ships with but you heavily disagree with many rule settings?

Say no more. Simply pass { blankSlate: true } to createConfig and you still benefit from automatic dependency detection, the general override setup based on file patterns, but every rule will be set to off.

This way, you can customize it entirely to your likings without having to create n overrides for rules and or rulesets.

Migrating a codebase to TypeScript

While in the process of migration, you may end up in a situation where you cannot turn on compilerOptions.checkJs from TypeScript itself due to e.g. builds breaking. However, by default certain rules will be disabled for JavaScript files because they are technically shadowed by TypeScript itself, e.g. no-undef.

You can opt out of this behaviour by either:

passing enableJavaScriptSpecificRulesInTypeScriptProject as true to createConfig
enabling compilerOptions.checkJs once you're there

Example:

const { createConfig } = require('eslint-config-galex/dist/createConfig');

module.exports = createConfig({
  enableJavaScriptSpecificRulesInTypeScriptProject: true,
});

Examples

Disabling a specific @typescript-eslint rule

const { createConfig } = require('eslint-config-galex/dist/createConfig');
const { getDependencies } = require('eslint-config-galex/dist/getDependencies');
const {
  createTypeScriptOverride,
} = require('eslint-config-galex/dist/overrides/typescript');

const dependencies = getDependencies();

const customTypescriptOverride = createTypeScriptOverride({
  ...dependencies,
  rules: {
    // here goes anything that applies **exclusively** to typescript files based on the `files` glob pattern also exported from ../overrides/typescript
    '@typescript-eslint/explicit-module-boundary-types': 'warn', // downgrading the default from "error" to "warn"
  },
});

module.exports = createConfig({
  overrides: [customTypescriptOverride],
});

Changing a eslint-plugin-unicorn rule specifically for React files

const { createConfig } = require('eslint-config-galex/dist/createConfig');
const { getDependencies } = require('eslint-config-galex/dist/getDependencies');
const {
  createReactOverride,
} = require('eslint-config-galex/dist/overrides/react');

const dependencies = getDependencies();

const customReactOverride = createReactOverride({
  ...dependencies,
  rules: {
    'unicorn/no-abusive-eslint-disable': 'off',
  },
});

module.exports = createConfig({
  overrides: [customReactOverride],
});

Adding plugins to any override

const { createConfig } = require('eslint-config-galex/dist/createConfig');
const { getDependencies } = require('eslint-config-galex/dist/getDependencies');
const {
  createReactOverride,
} = require('eslint-config-galex/dist/overrides/react');

const dependencies = getDependencies();

const customReactOverride = createReactOverride({
  ...dependencies,
  plugins: ['my-fancy-plugin'],
  rules: {
    'plugin/foo': 'warn',
    'plugin/bar': 'error',
    'plugin/baz': 'off',
  },
});

module.exports = createConfig({
  overrides: [customReactOverride],
});

Building your own config with the available exports

const { getDependencies } = require('eslint-config-galex/dist/getDependencies');
const {
  files,
  parser,
  defaultSettings,
} = require('eslint-config-galex/dist/overrides/react');

const dependencies = getDependencies();

const myReactOverride = {
  // using the internal react glob pattern
  files,
  // using the internal default react parser
  parser,
  // defining your custom rules
  rules: {
    'react/react-in-jsx-scope': 'warn',
  },
  // using the default settings
  settings: defaultSettings,
};

module.exports = {
  overrides: [myReactOverride],
  rules: {
    'no-await-in-loop': 'warn',
  },
};

I went through 30+ eslint-plugins so you don't have to.

Setting up ESLint can be easy.

Plug in someone's config or one of the many "industry standards" and be done with it. Eventually you learn that some of those practices maybe aren't the best idea. Too restrictive, treading into Prettier territory, conflicting with other rules, too opinionated or even outdated, you name it. What to do?

You begin adding // eslint-disable-next-line rulename-here. It works, but litters the code.

You begin disabling rules altogether. Maybe because you don't know better, or because the rule is actually bad for your situation. You begin to wonder.

You check npm and see there are ~~2.8k+ (August 2020)~~ 4.1k+ (December 2021) eslint-plugin-* packages out there. And even worse - 10k+ eslint-config-* packages. Which to choose? You sort by popularity and see some familiar faces. Time to install!

A few hours into stitching all those popular linting rules together you notice some rules collide, some rules are outdated, some expect others to be disabled, but only circumstantially. Enough!

"Now is the time to finally read through all rulesets and decide which I want!" you scream out loud, "it can't be that many!" - but find yourself finishing the first repo after 6 hours.

Setting up ESLint properly wasn't that easy after all.

Couldn't this be easier?

What makes this different than all the other configs out there?

It's incrementally adoptable! Usually you pick a config at one point in time: when starting a fresh project, or at least early on. Migrating later on, especially when working in teams with lots of code movement, you'd run into merging conflicts real quick.

Good news: you can use createConfig({ incrementalAdoption: true }) to downgrade all errors to warnings, and disable all warnings!

This allows you to introduce the config at an arbitrary point in time, while still profiting of it from minute one and still allows you to continue. Most urgent issues won't break the build - the best of both worlds!

Once you feel comfortable raising the reporting level, simply set incrementalAdoption to false or remove it from the arguments passed to createConfig.
Integration tests for all cases.
All internals, literally everything, is re-exported. Don't like some decision? Rules too weak? Want to add custom rules? Everything is covered!

This hopefully prevents the need of having to migrate between configs every once in a while which builds up frustration due to misconfiguration and the entire overhead related to that. Dependency injection, just for an eslint config!
This config has a heavy focus on code quality, best practices and tries to omit opinions.

What's included?

Everything is dynamically included based on your package.json and when using TypeScript, your tsconfig.json. Rules are selectively applied based on file name patterns.

All rules are commented and link to their docs.

[x] React
[x] Next.js
[x] Remix Run
[x] TypeScript
[x] Node.js
[x] jest
[x] jest-dom
[x] @testing-library
[x] prettier
[x] storybook & storybook/testing-library
[x] NestJS (with TypeScript)

Customization

All rulesets and overrides are created through functions accepting an object matching this schema:

interface Project {
  /**
   * whether `jest` is present
   */
  hasJest: boolean;
  /**
   * whether `@testing-library/jest-dom` is present
   */
  hasJestDom: boolean;
  /**
   * whether `@types/node` is present
   */
  hasNodeTypes: boolean;
  /**
   * whether any `@testing-library/<environment>` is present
   */
  hasTestingLibrary: boolean;
  /**
   * whether `@nestjs/core` is present
   */
  hasNest: boolean;
  storybook: {
    /**
     * whether any `@storybook/` is present that is not `@storybook/testing-library`
     */
    hasStorybook: boolean;
    /**
     * whether `@storybook/testing-library` is present
     */
    hasStorybookTestingLibrary: boolean;
  };
  typescript: {
    /**
     * whether `typescript` is present
     */
    hasTypeScript: boolean;
    /**
     * the installed version
     */
    version: string;
    /**
     * your tsConfig; used to detect feature availability
     */
    config?: object;
  };
  react: {
    /**
     * whether any flavour of react is present
     */
    hasReact: boolean;
    /**
     * whether `next` is present
     */
    isNext: boolean;
    /**
     *  whether `@remix-run/react` is present
     */
    isRemix: boolean;
    /**
     * whether `preact` is present
     * currently without effect
     */
    isPreact: boolean;
    /**
     * the installed version
     */
    version: string;
    /**
     * whether the project was bootstrapped with create-react-app
     */
    isCreateReactApp: boolean;
  };
  /**
   * your custom rules on top
   */
  rules?: object;
}

Available main exports:

This list only mentions the exports most people will need. For an exhaustive list, check out the source.

Overrides

const { createTypeScriptOverride } = require('eslint-config-galex/dist/overrides/typescript')
const { createReactOverride } = require('eslint-config-galex/dist/overrides/react')
const { createJestOverride } = require('eslint-config-galex/dist/overrides/jest')
const { createStorybookOverride } = require('eslint-config-galex/dist/overrides/storybook')

Please note that the test override should always come last.

Rulesets

const { createEslintCoreRules } = require('eslint-config-galex/dist/plugins/eslint-core')
const { createImportRules } = require('eslint-config-galex/dist/plugins/import')
const { createNextJsRules } = require('eslint-config-galex/dist/plugins/next')
const { createPromiseRules } = require('eslint-config-galex/dist/plugins/promise')
const { createSonarjsRules } = require('eslint-config-galex/dist/plugins/sonarjs')
const { createUnicornRules } = require('eslint-config-galex/dist/plugins/unicorn')

Examples

Custom TypeScript override to disable a rule

const { createConfig } = require('eslint-config-galex/dist/createConfig');
const {
  createTypeScriptOverride,
} = require('eslint-config-galex/dist/overrides/typescript');
const packageJson = require('./package.json');

// since `createTypeScriptOverride` is entirely configurable, we need to inform it about its environment
const tsOverrideConfig = {
  react: {
    hasReact: true,
  },
  rules: {
    '@typescript-eslint/ban-ts-comment': 'off',
  },
  typescript: {
    hasTypeScript: true,
    // sync with package.json should you upgrade TS
    version: packageJson.dependencies.typescript,
  },
};

// solely an override for TS
const tsOverride = createTypeScriptOverride(tsOverrideConfig);

// pass it into createConfig as array as it will be merged with the other overrides
module.exports = createConfig({ overrides: [tsOverride] });

Custom Jest override changing included `files`:

const { createConfig } = require('eslint-config-galex/dist/createConfig');
const { getDependencies } = require('eslint-config-galex/dist/getDependencies');
const {
  createJestOverride,
} = require('eslint-config-galex/dist/overrides/jest');

/**
 * override to enable jest globals for `/testUtils` folder
 */
const customJestLikeOverride = createJestOverride({
  ...getDependencies(),
  files: ['testUtils/*.ts?(x)'],
});

module.exports = createConfig({
  overrides: [customJestLikeOverride],
});