@keeex/eslint-config

Common eslint configuration

Installation

npm install -D @keeex/eslint-config

Usage

Create an eslint configuration file at the root of your project named .eslintrc.js containing the following:

const eslintConfig = require("@keeex/eslint-config");
module.exports = eslintConfig(
  {
    base: true,
    promise: true,
    jsx: true,
    import: true,
    reacthooks: true,
    reactnative: true,
    typescript: "./tsconfig.json",
    tsdoc: true,
    deprecation: true,
    mocha: true,
  },
  {
    env: {
      es2021: true,
      node: true,
    },
  },
);

The first argument is the configurations to pull-in. base is the generic JavaScript options, jsx add rules for React and JSX, reacthook add rules for React hooks and typescript add rules for TypeScript. For TypeScript, you can specify the name of your TypeScript configuration file, in which case more rules will be enabled.

The second argument is the base eslint configuration, to specify extra options that are not defined by the default configuration. It can be empty if not needed.

The default configuration is:

module.exports = {
  parser: "@typescript-eslint/parser", // only when typescript is enabled
  env: {
    es2021: true,
    node: true,
  },
  parserOptions: {
    ecmaVersion: "latest",
    sourceType: "module",
    project: "./tsconfig.json", // only for typescript
  },
  overrides: [
    {
      files: ["webres/**/*.js", "webres/**/*.ts"],
      env: {
        browser: true,
      },
    },
  ],
  extends: [ /\* enabled rule bases \*/ ],
  rules: { /\* enabled rules \*/ },
}

When specifying a base configuration, top-level properties will override these defaults, and automatic rules will in turn inject themselves in top-level. This mean that if you specify an overrides top-level property in the second argument of eslintConfig(), the default overrides value will not be used, but if a later rule (for typescript for example) have to populate overrides it will extend whatever the current value is.

It is also appropriate to append any local-only changes to the ouptut of the configuration function.

Promises

Some extra rules for promises can be used by setting promise to true (enabled by default).

Imports

Some extra rules for formatting and ordering imports can be used by setting import to true (enabled by default). It is possible to pass an object with the following properties instead of true:

{
  detectImportCycle: true,
}

All properties are true by default. Import cycle can be either false to disable it, true to enable it with a default depth of 3, or any number to control the maximum depth of the scan.

TypeScript

If typescript is set to true, only basic typescript rules are enforced. Instead, it is advised to provide the path to the typescript configuration file (typically tsconfig.json), in which case rules that requires typing informations are enabled.

TSDoc

For TypeScript projects, the eslint-plugin-tsdoc is enabled by default. To disable it, use the tsdoc config property set to false.

Deprecation

Warn when using deprecated calls/properties. This only work with TypeScript enabled with project types.

React/JSX

To improve handling of React/JSX, set jsx to true. It is also possible to pass a string indicating the expected React version. If not specified, will set to "detect" and use the version installed in the project.

React Hooks

To enable some more rules for React Hooks, set reacthooks to true,

React Native

To enable some more rules for React Native, set reactnative to true.

Mocha testsuite

To enable mocha-specific rules, as well as loosen some regular rules for testing, set mocha to true. Fine-tuned control is possible by providing an object instead of true with the following properties:

{
  fileFilter: [
    "**/*.test.ts",
    "**/*.test.js",
    "**/testutils.ts",
    "**/testutils.js",
    "tests/**/*.ts",
    "tests/**/*.js",
    "test/**/*.ts",
    "test/**/*.js",
  ],
  expectHelper: true,
}

All value optional, default values are the ones specified above. fileFilter is the overrides files definition to apply the test settings to. expectHelper relax some eslint rules to handle the use of expect-like assertions in test files.

Dependencies

Depend on eslint. If typescript is enabled, @typescript-eslint/eslint-plugin, @typescript-eslint/parser, eslint-plugin-tsdoc must be installed. If deprecation is enabled, eslint-plugin-deprecation must be installed. If React/JSX is enabled, eslint-plugin-react must be installed. If React Hooks is enabled, eslint-plugin-react-hooks must be installed. If React Native is enabled, eslint-plugin-react-native must be installed. Promise support requires eslint-plugin-promise. If mocha is used as the testsuite, eslint-plugin-mocha must be installed. Import support requires eslint-plugin-i.

Automatic dependency check

You can run the binary npx eslint-depcheck to check if all the currently required dependencies are installed. Add the flag auto to automatically install missing one/remove old ones.