jsenvEslintRules.js

/*
 * Contains configuration of many ESLint rules with the following mindset:
 * 1. ESLint should fail only for important things
 * 2. ESLint should be silent as long as nothing critical is detected
 * 3. When code is slighly modified to test/debug something, please ESLint, let me do without
 *    bothering me with "best practices" and stuff
 *
 * Notes:
 * - Point 3. is the reason why rules like "prefer-const" are disabled
 * - It's on purpose that point "2." is an other way of phrasing "1."
 * - There is a few exception to mindset, for example "no-eval" is not really
 *   critical but the rule is still enabled
 *
 * See also:
 * - https://eslint.org/docs/rules/
 */

export const jsenvEslintRules = {
  "accessor-pairs": ["error"],
  "array-bracket-spacing": ["error", "never"],
  "array-callback-return": ["error"],
  "arrow-parens": ["error", "as-needed"],
  "arrow-spacing": ["error", { before: true, after: true }],
  "block-scoped-var": ["error"],
  "brace-style": ["error", "stroustrup"],
  "camelcase": [
    "off",
    {
      properties: "always",
    },
  ],
  "comma-dangle": [
    "error",
    {
      arrays: "only-multiline",
      objects: "only-multiline",
      imports: "only-multiline",
      exports: "only-multiline",
      functions: "only-multiline",
    },
  ],
  "comma-spacing": [
    "error",
    {
      before: false,
      after: true,
    },
  ],
  "comma-style": ["error", "last"],
  "computed-property-spacing": ["error", "never"],
  "consistent-return": ["error"],
  "constructor-super": ["error"],
  "curly": ["error"],
  "default-case": ["error"],
  "dot-location": ["error", "property"],
  "dot-notation": ["error"],
  "eol-last": ["off"],
  "eqeqeq": ["error"],
  "generator-star-spacing": ["error", "both"],
  "getter-return": ["error"],
  "grouped-accessor-pairs": ["error"],
  "guard-for-in": ["error"],
  "handle-callback-err": ["warn"],
  /**
   * "tab" is theorically a better option so that people can choose identation width.
   * Because it allow them to decide how much space a tab char takes (2, 4, 100) in their environment
   * But it comes with several issue:
   * - By default github will render a tab with 8 spaces
   * (can be fixed thank to an .editorconfig at the root of the github project (see http://stackoverflow.com/a/33831598)
   * - A user cannot globally defined how much space a tab should take
   * In a perfect world it would be an operating system setting that browser
   * would follow.
   *
   * In practice spaces cause less troubles.
   */
  "indent": ["error", 2, { SwitchCase: 1 }],
  "jsx-quotes": ["error"],
  "key-spacing": [
    "error",
    {
      beforeColon: false,
      afterColon: true,
    },
  ],
  "keyword-spacing": ["error"],
  // disabled otherwise fails when eslint is runned on windows
  // after a git clone
  "linebreak-style": ["off", "unix"],
  "max-len": [
    "warn",
    120,
    4,
    {
      ignoreComments: true,
      ignoreUrls: true,
      ignorePattern: "^\\s*var\\s.+=\\s.+\\/.*?\\/;$",
    },
  ],
  "max-nested-callbacks": ["warn", 4],
  "new-cap": [
    "error",
    {
      newIsCap: true,
      capIsNew: false,
    },
  ],
  "new-parens": ["error"],
  "no-alert": ["error"],
  "no-array-constructor": ["error"],
  "no-caller": ["error"],
  "no-case-declarations": ["error"],
  "no-class-assign": ["error"],
  "no-cond-assign": ["error"],
  "no-confusing-arrow": ["error"],
  "no-const-assign": ["error"],
  "no-constant-condition": ["error"],
  "no-constant-binary-expression": ["error"],
  "no-constructor-return": ["error"],
  "no-control-regex": ["error"],
  "no-debugger": process.env.CI ? ["error"] : ["off"],
  "no-delete-var": ["error"],
  "no-div-regex": ["error"],
  "no-dupe-args": ["error"],
  "no-duplicate-case": ["error"],
  "no-dupe-class-members": ["error"],
  "no-dupe-else-if": ["error"],
  "no-dupe-keys": ["error"],
  "no-else-return": ["error"],
  "no-empty-character-class": ["error"],
  "no-empty-pattern": ["error"],
  "no-eq-null": ["error"],
  "no-extend-native": ["error"],
  "no-ex-assign": ["error"],
  "no-extra-bind": ["error"],
  "no-extra-boolean-cast": ["error"],
  "no-extra-label": ["error"],
  "no-extra-semi": ["off"],
  // At first I wanted to disable "no-eval" because every one knows eval is a bad idea
  // so when it's used it's always for a good reason.
  // But on second thought it's better to disable the rule
  // locally using "//eslint-disable-next-line no-eval" in that case
  "no-eval": ["error"],
  "no-fallthrough": ["error"],
  "no-floating-decimal": ["error"],
  "no-func-assign": ["error"],
  "no-inner-declarations": ["error"],
  "no-invalid-regexp": ["error"],
  "no-implicit-coercion": ["error"],
  "no-implicit-globals": ["error"],
  "no-implied-eval": ["error"],
  "no-irregular-whitespace": ["error"],
  "no-iterator": ["error"],
  "no-label-var": ["error"],
  "no-labels": ["off"], // https://gist.github.com/getify/706e5e10822a298375da40f9cc1fa295
  "no-lone-blocks": ["off"], // https://gist.github.com/getify/706e5e10822a298375da40f9cc1fa295
  "no-lonely-if": ["error"],
  "no-loop-func": ["error"],
  "no-magic-numbers": ["off"],
  "no-mixed-requires": ["error", { grouping: true, allowCall: true }],
  "no-mixed-spaces-and-tabs": ["error"],
  "no-multi-spaces": ["error"],
  "no-multi-str": ["error"],
  "no-multiple-empty-lines": ["off", { max: 1 }],
  "no-native-reassign": ["error"],
  "no-negated-condition": ["error"],
  // disabled because deprecated in favor of no-unsafe-negation
  // https://eslint.org/docs/rules/no-negated-in-lhs
  "no-negated-in-lhs": ["off"],
  // I prefer when ESLint really has something to say
  // nested ternary are not wrong, especially when prettier
  // format them correctly
  // In the end, they often gets transformed to helper function
  // but in the meantime eslint is complaining
  "no-nested-ternary": ["off"],
  "no-new": ["error"],
  "no-new-func": ["error"],
  "no-new-require": ["error"],
  "no-new-object": ["error"],
  "no-new-symbol": ["error"],
  "no-new-wrappers": ["error"],
  "no-obj-calls": ["error"],
  "no-octal": ["error"],
  "no-octal-escape": ["error"],
  "no-path-concat": ["error"],
  "no-proto": ["error"],
  "no-redeclare": ["error"],
  "no-regex-spaces": ["error"],
  "no-restricted-imports": [
    "error",
    "domain",
    "freelist",
    "smalloc",
    "sys",
    "colors",
  ],
  "no-restricted-modules": [
    "error",
    "domain",
    "freelist",
    "smalloc",
    "sys",
    "colors",
  ],
  "no-restricted-syntax": ["error", "WithStatement"],
  "no-return-assign": ["error", "always"],
  "no-setter-return": ["error"],
  "no-script-url": ["error"],
  "no-self-assign": ["error"],
  "no-self-compare": ["error"],
  "no-sequences": ["error"],
  "no-shadow-restricted-names": ["error"],
  "no-spaced-func": ["error"],
  "no-sparse-arrays": ["error"],
  "no-this-before-super": ["error"],
  "no-throw-literal": ["error"],
  "no-trailing-spaces": ["error"],
  "no-undef": ["error", { typeof: true }],
  "no-undef-init": ["error"],
  "no-undefined": ["off"],
  "no-unexpected-multiline": ["error"],
  "no-unmodified-loop-condition": ["error"],
  "no-unneeded-ternary": ["error"],
  "no-unreachable": ["error"],
  "no-unused-expressions": ["error"],
  "no-unused-labels": ["off"], // https://gist.github.com/getify/706e5e10822a298375da40f9cc1fa295
  "no-unused-private-class-members": ["error"],
  "no-unused-vars": ["error"],
  "no-use-before-define": [
    "error",
    /*
     * "no-use-before-define" is great to prevent a common mistake
     * where code tries to use a variable before it's actually available.
     * In practice this rule fails even on valid code.
     * Enabling the default options of this rule would
     * force variables,functions and classes to be declared in specific order
     * which is very annoying because:
     * - code is valid in the first place
     * - it's SUPER NICE to put variables and functions that are
     *   implementation details at the bottom of the file to make
     *   important code more accesible
     */
    {
      functions: false,
      variables: false,
      classes: false,
      allowNamedExports: true,
    },
  ],
  "no-useless-call": ["error"],
  "no-useless-concat": ["error"],
  "no-useless-constructor": ["error"],
  "no-void": ["error"],
  "no-warning-comments": ["off"],
  "no-whitespace-before-property": ["error"],
  "no-with": ["error"],
  "object-curly-spacing": ["error", "always"],
  "object-shorthand": ["warn", "always"],
  "one-var": ["error", "never"],
  "one-var-declaration-per-line": ["error"],
  // Sometimes I prefer to write toto = toto + 1
  // instead of toto++ for whatever reason
  // and having ESLint to complain is annoying
  // I prefer when ESLint really has something to say
  "operator-assignment": ["off", "always"],
  "operator-linebreak": [
    "error",
    "after",
    {
      overrides: { "?": "ignore", ":": "ignore" },
    },
  ],
  "padded-blocks": ["error", "never"],
  // I prefer to use const to indicate immediatly to the reader
  // that this variable is never re-assigned. let becomes
  // the exception and it helps to understand the code.
  // However during development a variable gets used once
  // and should be const, then you reuse it, and should be let.
  // I prefer ESLint to stay quiet during these moments.
  // I already got the habit of using const and would not care
  // if some let where to stay by mistake.
  "prefer-const": [
    "off",
    {
      destructuring: "all",
      ignoreReadBeforeAssign: true,
    },
  ],
  // Math.pow is cool, why being so strict ?
  "prefer-exponentiation-operator": ["off"],
  "prefer-rest-params": ["warn"],
  "prefer-spread": ["warn"],
  "prefer-template": ["warn"],
  "quote": [
    // disabled because it becomes painfull when switching
    // between "" and `` (template literals)
    "off",
    // double because closer to .json, this it increase compatibility between .js and .json
    // also because ' are often used in english and '' would lead to 'I\'m' VS "I'm"
    "double",
  ],
  "quote-props": [
    "error",
    "as-needed",
    {
      keywords: false,
      numbers: true,
      // unnecessary: false so that when you fall into edge cases
      // you can use the quoting style you want
      unnecessary: false,
    },
  ],
  "semi": ["error", "always"],
  "semi-spacing": [
    "error",
    {
      before: false,
      after: true,
    },
  ],
  "space-before-blocks": ["error", "always"],
  "space-before-function-paren": ["error", "never"],
  "space-in-parens": ["error", "never"],
  "space-infix-ops": ["error"],
  "space-unary-ops": ["error"],
  "spaced-comment": [
    "error",
    "always",
    {
      markers: ["!"],
    },
  ],
  "template-curly-spacing": ["error"],
  "use-isnan": ["error"],
  "valid-jsdoc": [
    "off",
    {
      requireReturn: false,
      prefer: {
        returns: "return",
      },
    },
  ],
  "valid-typeof": ["error"],
  "wrap-iife": ["error", "inside"],
  "yield-star-spacing": ["error", "both"],
  "yoda": ["error"],
};