.eslintrc.js

"use strict";

const {
  es5Paths,
  esNextPaths
} = require("./scripts/shared/pathsByLanguageVersion");

const OFF = 0;
const ERROR = 2;

module.exports = {
  extends: "fbjs",

  // Stop ESLint from looking for a configuration file in parent folders
  root: true,

  plugins: ["jest", "no-for-of-loops"],

  parser: "babel-eslint",
  parserOptions: {
    ecmaVersion: 8,
    sourceType: "module",
    ecmaFeatures: {
      experimentalObjectRestSpread: true
    }
  },

  // We're stricter than the default config, mostly. We'll override a few rules
  // and then enable some specific ones.
  rules: {
    "accessor-pairs": OFF,
    "brace-style": [ERROR, "1tbs"],
    // 'comma-dangle': [ERROR, 'always-multiline'],
    "consistent-return": OFF,
    "dot-location": [ERROR, "property"],
    "dot-notation": ERROR,
    "eol-last": ERROR,
    eqeqeq: [ERROR, "allow-null"],
    indent: OFF,
    "jsx-quotes": [ERROR, "prefer-double"],
    "keyword-spacing": [ERROR, { after: true, before: true }],
    "no-bitwise": OFF,
    "no-inner-declarations": [ERROR, "functions"],
    "no-multi-spaces": ERROR,
    "no-restricted-syntax": [ERROR, "WithStatement"],
    "no-shadow": ERROR,
    "no-unused-expressions": ERROR,
    "no-unused-vars": [ERROR, { args: "none" }],
    "no-use-before-define": OFF,
    "no-useless-concat": OFF,
    quotes: [
      ERROR,
      "single",
      { avoidEscape: true, allowTemplateLiterals: true }
    ],
    "space-before-blocks": ERROR,
    "space-before-function-paren": OFF,
    "valid-typeof": [ERROR, { requireStringLiterals: true }],

    // We apply these settings to files that should run on Node.
    // They can't use JSX or ES6 modules, and must be in strict mode.
    // They can, however, use other ES6 features.
    // (Note these rules are overridden later for source files.)
    "no-var": ERROR,
    strict: ERROR,

    // Enforced by Prettier
    // TODO: Prettier doesn't handle long strings or long comments. Not a big
    // deal. But I turned it off because loading the plugin causes some obscure
    // syntax error and it didn't seem worth investigating.
    "max-len": OFF,

    // Prevent for...of loops because they require a Symbol polyfill.
    // You can disable this rule for code that isn't shipped (e.g. build scripts and tests).
    "no-for-of-loops/no-for-of-loops": ERROR
  },

  overrides: [
    {
      // We apply these settings to files that we ship through npm.
      // They must be ES5.
      files: es5Paths,
      parser: "espree",
      parserOptions: {
        ecmaVersion: 5,
        sourceType: "script"
      },
      rules: {
        "no-var": OFF,
        strict: ERROR
      }
    },
    {
      // We apply these settings to the source files that get compiled.
      // They can use all features including JSX (but shouldn't use `var`).
      files: esNextPaths,
      parser: "babel-eslint",
      parserOptions: {
        ecmaVersion: 8,
        sourceType: "module"
      },
      rules: {
        "no-var": ERROR,
        strict: OFF
      }
    },
    {
      files: ["**/__tests__/*.js"],
      rules: {
        // https://github.com/jest-community/eslint-plugin-jest
        "jest/no-focused-tests": ERROR,
        "jest/valid-expect": ERROR,
        "jest/valid-expect-in-promise": ERROR
      }
    }
  ],

  globals: {
    SharedArrayBuffer: true,

    spyOnDev: true,
    spyOnDevAndProd: true,
    spyOnProd: true,
    __PROFILE__: true,
    __UMD__: true,
    __EXPERIMENTAL__: true,
    trustedTypes: true
  },

  settings: {
    react: {
      pragma: "Ganic"
    }
  }
};