eslint-config-vtex/rules/best-practices.js

VTEX's eslint config

module.exports = {
  rules: {
    // Enforces return statements in callbacks of array's methods
    // https://eslint.org/docs/rules/array-callback-return
    'array-callback-return': ['error', { allowImplicit: true }],

    // Treat var statements as if they were block scoped
    // https://eslint.org/docs/rules/block-scoped-var
    'block-scoped-var': 'error',

    // Require default case in switch statements
    // https://eslint.org/docs/rules/default-case
    'default-case': ['error', { commentPattern: '^no default$' }],

    // Disallow case statement fallthrough
    // https://eslint.org/docs/rules/no-fallthrough
    'no-fallthrough': [
      'error',
      {
        commentPattern: '(break[\\s\\w]*omitted|falls\\s?through)',
      },
    ],

    // Enforce parameters with default values to be last
    // https://eslint.org/docs/rules/default-param-last
    'default-param-last': 'error',

    // Encourages use of dot notation whenever possible
    // https://eslint.org/docs/rules/dot-notation
    'dot-notation': ['error', { allowKeywords: true }],

    // Require the use of === and !==
    // https://eslint.org/docs/rules/eqeqeq
    eqeqeq: ['error', 'always', { null: 'ignore' }],

    // Require grouped accessor pairs in object literals and classes
    // https://eslint.org/docs/rules/grouped-accessor-pairs
    'grouped-accessor-pairs': 'error',

    // Enforce a maximum number of classes per file
    // https://eslint.org/docs/rules/max-classes-per-file
    // TODO, maybe turn on
    'max-classes-per-file': ['off', 1],

    // Disallow the use of alert, confirm, and prompt
    // https://eslint.org/docs/rules/no-alert
    'no-alert': 'warn',

    // Disallow use of arguments.caller or arguments.callee
    // https://eslint.org/docs/rules/no-caller
    'no-caller': 'error',

    // Disallow lexical declarations in case/default clauses
    // https://eslint.org/docs/rules/no-case-declarations
    'no-case-declarations': 'error',

    // Disallow returning value in constructor
    // https://eslint.org/docs/rules/no-constructor-return
    'no-constructor-return': 'error',

    // Disallow else after a return in an if
    // https://eslint.org/docs/rules/no-else-return
    'no-else-return': ['error', { allowElseIf: false }],

    // Disallow empty functions, except for standalone funcs/arrows
    // https://eslint.org/docs/rules/no-empty-function
    'no-empty-function': [
      'error',
      {
        allow: ['arrowFunctions', 'functions', 'methods'],
      },
    ],

    // Disallow use of eval()
    // https://eslint.org/docs/rules/no-eval
    'no-eval': 'error',

    // Disallow adding to native types
    // https://eslint.org/docs/rules/no-extend-native
    'no-extend-native': 'error',

    // Disallow unnecessary function binding
    // https://eslint.org/docs/rules/no-extra-bind
    'no-extra-bind': 'error',

    // Disallow Unnecessary Labels
    // https://eslint.org/docs/rules/no-extra-label
    'no-extra-label': 'error',

    // Disallow the use of leading or trailing decimal points in numeric literals
    // https://eslint.org/docs/rules/no-floating-decimal
    // Disabled because prettier already handle this rule
    'no-floating-decimal': 'off',

    // Disallow reassignments of native objects or read-only globals
    // https://eslint.org/docs/rules/no-global-assign
    'no-global-assign': 'error',

    // Disallow use of eval()-like methods
    // https://eslint.org/docs/rules/no-implied-eval
    'no-implied-eval': 'error',

    // Disallow usage of __iterator__ property
    // https://eslint.org/docs/rules/no-iterator
    'no-iterator': 'error',

    // Disallow use of labels for anything other then loops and switches
    // https://eslint.org/docs/rules/no-labels
    'no-labels': 'error',

    // Disallow unnecessary nested blocks
    // https://eslint.org/docs/rules/no-lone-blocks
    'no-lone-blocks': 'error',

    // Disallow creation of functions within loops
    // https://eslint.org/docs/rules/no-loop-func
    'no-loop-func': 'error',

    // Disallow magic numbers
    // https://eslint.org/docs/rules/no-magic-numbers
    // TODO enable? maybe too much
    'no-magic-numbers': [
      'off',
      {
        ignore: [0, 1, 2, 3],
        ignoreArrayIndexes: true,
        enforceConst: true,
        detectObjects: false,
      },
    ],

    // Disallow use of multiline strings
    // https://eslint.org/docs/rules/no-multi-str
    'no-multi-str': 'error',

    // Disallow use of new operator for Function object
    // https://eslint.org/docs/rules/no-new-func
    'no-new-func': 'error',

    // Disallows creating new instances of String, Number, and Boolean
    // https://eslint.org/docs/rules/no-new-wrappers
    'no-new-wrappers': 'error',

    // Disallow use of octal escape sequences in string literals, such as
    // var foo = 'Copyright \251';
    // https://eslint.org/docs/rules/no-octal-escape
    'no-octal-escape': 'error',

    // Disallow usage of __proto__ property
    // https://eslint.org/docs/rules/no-proto
    'no-proto': 'error',

    // Disallow declaring the same variable more then once
    // https://eslint.org/docs/rules/no-redeclare
    'no-redeclare': 'error',

    // Disallow use of assignment in return statement
    // https://eslint.org/docs/rules/no-return-assign
    'no-return-assign': ['error', 'except-parens'],

    // Disallow redundant `return await`
    // https://eslint.org/docs/rules/no-return-await
    'no-return-await': 'error',

    // Disallow use of `javascript:` urls.
    // https://eslint.org/docs/rules/no-script-url
    'no-script-url': 'error',

    // Disallow comparisons where both sides are exactly the same
    // https://eslint.org/docs/rules/no-self-compare
    'no-self-compare': 'error',

    // Disallow use of comma operator
    // https://eslint.org/docs/rules/no-sequences
    'no-sequences': 'error',

    // Disallow unused labels
    // https://eslint.org/docs/rules/no-unused-labels
    'no-unused-labels': 'error',

    // Disallow unnecessary catch clauses
    // https://eslint.org/docs/rules/no-useless-catch
    // TODO enable?
    'no-useless-catch': 'off',

    // Disallow unnecessary string escaping
    // https://eslint.org/docs/rules/no-useless-escape
    'no-useless-escape': 'error',

    // Disallow redundant return; keywords
    // https://eslint.org/docs/rules/no-useless-return
    'no-useless-return': 'error',

    // Disallow use of void operator
    // https://eslint.org/docs/rules/no-void
    'no-void': 'error',

    // Prefer using regex literals instead of constructor
    // https://eslint.org/docs/rules/prefer-regex-literals
    'prefer-regex-literals': 'warn',

    // Require use of the second argument for parseInt()
    // https://eslint.org/docs/rules/radix
    radix: 'error',

    // Requires to declare all vars on top of their containing scope
    // https://eslint.org/docs/rules/vars-on-top
    'vars-on-top': 'error',
    // https://eslint.org/docs/rules/constructor-super
    'constructor-super': 'error',

    // Disallow useless computed property keys
    // https://eslint.org/docs/rules/no-useless-computed-key
    'no-useless-computed-key': 'error',

    // Disallow unnecessary constructor
    // https://eslint.org/docs/rules/no-useless-constructor
    'no-useless-constructor': 'error',

    // Disallow renaming import, export, and destructured assignments to the same name
    // https://eslint.org/docs/rules/no-useless-rename
    'no-useless-rename': ['error'],

    // Require let or const instead of var
    // https://eslint.org/docs/rules/no-var
    'no-var': 'error',

    // Require method and property shorthand syntax for object literals
    // https://eslint.org/docs/rules/object-shorthand
    'object-shorthand': [
      'error',
      'always',
      {
        ignoreConstructors: false,
        avoidQuotes: true,
      },
    ],

    // Suggest using arrow functions as callbacks
    // https://eslint.org/docs/rules/prefer-arrow-callback
    // TODO discussion
    'prefer-arrow-callback': [
      'off',
      {
        allowNamedFunctions: false,
        allowUnboundThis: true,
      },
    ],

    // Suggest using of const declaration for variables that are never modified after declared
    // https://eslint.org/docs/rules/prefer-const
    'prefer-const': [
      'error',
      {
        destructuring: 'all',
        ignoreReadBeforeAssign: true,
      },
    ],

    // Prefer destructuring from arrays and objects
    // https://eslint.org/docs/rules/prefer-destructuring
    'prefer-destructuring': [
      'warn',
      {
        VariableDeclarator: {
          array: true,
          object: true,
        },
        AssignmentExpression: {
          array: false,
          object: false,
        },
      },
      {
        enforceForRenamedProperties: false,
      },
    ],

    // Disallow parseInt() in favor of binary, octal, and hexadecimal literals
    // https://eslint.org/docs/rules/prefer-numeric-literals
    'prefer-numeric-literals': 'error',

    // Use rest parameters instead of arguments
    // https://eslint.org/docs/rules/prefer-rest-params
    'prefer-rest-params': 'error',

    // Suggest using the spread operator instead of .apply()
    // https://eslint.org/docs/rules/prefer-spread
    'prefer-spread': 'error',

    // Suggest using template literals instead of string concatenation
    // https://eslint.org/docs/rules/prefer-template
    'prefer-template': 'warn',

    // Disallow generator functions that do not have yield
    // https://eslint.org/docs/rules/require-yield
    'require-yield': 'error',

    // Require a Symbol description
    // https://eslint.org/docs/rules/symbol-description
    'symbol-description': 'error',
  },
}