`@jjangga0214/eslint-configurer`

This is NOT a Sharable Config for eslint. Rather, it provides functions to easily create an eslint config. Thus, its concept is similar to sharable config. You can create Sharable Config by depending on this package. In fact, Sharable Config @jjangga0214/eslint-config depends on this package.

Installation

npm install --save-dev @jjangga0214/eslint-configurer
# or
yarn add --dev @jjangga0214/eslint-configurer
# or
pnpm add --save-dev @jjangga0214/eslint-configurer

And you should also install peerDependencies manually. Checkout package.json or npm info.

# This does not install them all. This just show them on terminal.
npm info "@jjangga0214/eslint-configer@latest" peerDependencies

Or install them all by install-peerdeps.

# For npm
npx install-peerdeps --dev @jjangga0214/eslint-config
# For yarn
npx install-peerdeps --yarn --dev @jjangga0214/eslint-config
# For pnpm
npx install-peerdeps --pnpm --dev @jjangga0214/eslint-config

But before the installtion, please read this docs first.

Optional `peerDependencies`

As you can see from peerDependenciesMeta in package.json, some peerDependencies are marked as optional. For peerDependencies NOT specified as optional, you must install them.

When you ONLY use javascript (.js, .mjs, .cjs)

You don't have to install optional peerDependencies at all. You still have to install non-optional peerDependencies (e.g. eslint, prettier, eslint-plugin-unicorn).

When you use typescript (.ts, .tsx)

If you use typescript, you should install these optional peerDependencies. (So these are in fact NOT optional if you use typescript.)

@typescript-eslint/eslint-plugin
eslint-import-resolver-typescript
eslint-plugin-import (This is needed both for typescript and react)
typescript

When you use react (.jsx, .tsx)

If you use react, you should install these optional peerDependencies. (So these are in fact NOT optional if you use react.)

eslint-plugin-import (This is needed both for typescript and react)
eslint-plugin-jsx-a11y
eslint-plugin-react
eslint-plugin-react-hooks

Why are these 3 packages listed on both `peerDependencies` and `dependencies` simultaneously?

eslint-plugin-jsx-a11y
eslint-plugin-react
eslint-plugin-react-hooks

Theses packages above are listed on both dependencies and peerDependencies. One of this pacakges dependency, eslint-config-airbnb, which contains react rules along with pure javascript rules, requires them as peerDependencies. Though it's possible letting the final consumer install them as dependencies, it's avoided intentionally by listing them in this package's dependencies.

This is because I don't want to force the final users to install those plugins even when their projects don't include react code.

Therefore I let those plugins become optional peerDependencies to the final consumer by specifying them as dependencies in this package's package.json.

For users who use react, they have to install the plugins anyway (So it's in fact not optional). For users who don't use react, they don't have to install the plugins.

Usage

.eslintrc.js:

const { configure } = require('@jjangga0214/eslint-configurer');

module.exports = configure({
  react: true,
  typescript: true,
  jest: true,
})

If you have tsconfig named/located unconventional

By default, ./packages/*/tsconfig.json or (if not found) ./tsconfig.json is used. If your tsconfig file is named/located differently (e.g. tsconfig.eslint.json), then you might want to override parserOptions.project AND settings['import/resolver'].typescript.project from typescript config.

parserOptions: {  
  project: ['./packages/*/tsconfig.json', './tsconfig.json',], // Override it
},
settings: {
  'import/parsers': {
    '@typescript-eslint/parser': [".ts", ".tsx"]
  },
  'import/resolver': {
    typescript: {
      alwaysTryTypes: true,
      project: [ // Override this as well
        'packages/*/tsconfig.json',
        'tsconfig.json',
      ]
    },
  },
}

Development

`Sharable Config`

You should understand what eslint's concept of sharable config. The official docs is here.

Plugins are `peerDependencies`, while Sharable Configs are `dependencies`

Sharable Config can depend on other Sharable Configs. Therefore the final consumer does not need to manually install all Sharable Configs. They are all to be installed transitively (dependency of dependency).

Once eslint#3458 is resolved, Plugins can be moved from peerDependencies to dependencies. Currently, only eslint-config-* are allowed to be dependencies.

Why using `require.resolve`?

As you can see require.resolve is used for extend field in config. Eslint extract sharable config name from omited prefix eslint-config.

{
  'extends': [
    'eslint:recommended', // "eslint:" protocol is reserved for eslint itself 
    'plugin:unicorn/recommended', // "plugin:" protocol is a must for plugins
    'airbnb', // This is specifying "eslint-config-airbnb". The prefix "eslint-config" can be ommitted.
  ]
}

However, this only works when you directly configure eslint for your project. For, a Sharable Config depending on other Sharable Configs, this does not work. Therefore, a full path should be specified. This is why require.resolve is used.

{
  'extends': [
    'eslint:recommended',
    'plugin:unicorn/recommended',
    require.resolve('eslint-config-airbnb'), 
  ]
}