eslintrc.js

const restrictedGlobals = [
  'addEventListener',
  'blur',
  'close',
  'closed',
  'confirm',
  'defaultStatus',
  'defaultstatus',
  'event',
  'external',
  'find',
  'focus',
  'frameElement',
  'frames',
  'history',
  'innerHeight',
  'innerWidth',
  'length',
  'location',
  'locationbar',
  'menubar',
  'moveBy',
  'moveTo',
  'name',
  'onblur',
  'onerror',
  'onfocus',
  'onload',
  'onresize',
  'onunload',
  'open',
  'opener',
  'opera',
  'outerHeight',
  'outerWidth',
  'pageXOffset',
  'pageYOffset',
  'parent',
  'print',
  'removeEventListener',
  'resizeBy',
  'resizeTo',
  'screen',
  'screenLeft',
  'screenTop',
  'screenX',
  'screenY',
  'scroll',
  'scrollbars',
  'scrollBy',
  'scrollTo',
  'scrollX',
  'scrollY',
  'self',
  'status',
  'statusbar',
  'stop',
  'toolbar',
  'top',
];

module.exports = {
  root: true,

  env: {
    browser: true,
    commonjs: true,
    es6: true,
    jest: true,
    node: true,
  },

  parserOptions: {
    ecmaVersion: 6,
    sourceType: 'module',
    ecmaFeatures: {
      jsx: true,
      generators: true,
      experimentalObjectRestSpread: true,
    },
  },

  globals: {
    _: false,
    $: false,
    $$: false,
  },

  parser: 'babel-eslint',

  rules: {
    // enforces getter/setter pairs in objects
    'accessor-pairs': 'off',

    // enforces return statements in callbacks of array's methods
    // http://eslint.org/docs/rules/array-callback-return
    'array-callback-return': 'error',

    // treat var statements as if they were block scoped
    'block-scoped-var': 'error',

    // specify the maximum cyclomatic complexity allowed in a program
    complexity: ['off', 11],

    // enforce that class methods use "this"
    // http://eslint.org/docs/rules/class-methods-use-this
    'class-methods-use-this': ['error', {
      exceptMethods: [],
    }],

    // require return statements to either always or never specify values
    'consistent-return': 'error',

    // specify curly brace conventions for all control statements
    curly: ['error', 'multi-line'],

    // require default case in switch statements
    'default-case': ['error', { commentPattern: '^no default$' }],

    // encourages use of dot notation whenever possible
    'dot-notation': ['error', { allowKeywords: true }],

    // enforces consistent newlines before or after dots
    // http://eslint.org/docs/rules/dot-location
    'dot-location': ['error', 'property'],

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

    // make sure for-in loops have an if statement
    'guard-for-in': 'error',

    // disallow the use of alert, confirm, and prompt
    'no-alert': 'warn',

    // disallow use of arguments.caller or arguments.callee
    'no-caller': 'error',

    // disallow lexical declarations in case/default clauses
    // http://eslint.org/docs/rules/no-case-declarations.html
    'no-case-declarations': 'error',

    // disallow division operators explicitly at beginning of regular expression
    // http://eslint.org/docs/rules/no-div-regex
    'no-div-regex': 'off',

    // disallow else after a return in an if
    // https://eslint.org/docs/rules/no-else-return
    // TODO: semver-major, set allowElseIf to false
    'no-else-return': ['error', { allowElseIf: true }],

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

    // disallow empty destructuring patterns
    // http://eslint.org/docs/rules/no-empty-pattern
    'no-empty-pattern': 'error',

    // disallow comparisons to null without a type-checking operator
    'no-eq-null': 'off',

    // disallow use of eval()
    'no-eval': 'error',

    // disallow adding to native types
    'no-extend-native': 'error',

    // disallow unnecessary function binding
    'no-extra-bind': 'error',

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

    // disallow fallthrough of case statements
    'no-fallthrough': 'error',

    // disallow the use of leading or trailing decimal points in numeric literals
    'no-floating-decimal': 'error',

    // disallow reassignments of native objects or read-only globals
    // http://eslint.org/docs/rules/no-global-assign
    'no-global-assign': ['error', { exceptions: [] }],
    // deprecated in favor of no-global-assign
    'no-native-reassign': 'off',

    // disallow implicit type conversions
    // http://eslint.org/docs/rules/no-implicit-coercion
    'no-implicit-coercion': ['off', {
      boolean: false,
      number: true,
      string: true,
      allow: [],
    }],

    // disallow var and named functions in global scope
    // http://eslint.org/docs/rules/no-implicit-globals
    'no-implicit-globals': 'off',

    // disallow use of eval()-like methods
    'no-implied-eval': 'error',

    // disallow this keywords outside of classes or class-like objects
    'no-invalid-this': 'off',

    // disallow usage of __iterator__ property
    'no-iterator': 'error',

    // disallow use of labels for anything other then loops and switches
    'no-labels': ['error', { allowLoop: false, allowSwitch: false }],

    // disallow unnecessary nested blocks
    'no-lone-blocks': 'error',

    // disallow creation of functions within loops
    'no-loop-func': 'error',

    // disallow magic numbers
    // http://eslint.org/docs/rules/no-magic-numbers
    'no-magic-numbers': ['off', {
      ignore: [],
      ignoreArrayIndexes: true,
      enforceConst: true,
      detectObjects: false,
    }],

    // disallow use of multiple spaces
    'no-multi-spaces': ['error', {
      ignoreEOLComments: false,
    }],

    // disallow use of multiline strings
    'no-multi-str': 'error',

    // disallow use of new operator when not part of the assignment or comparison
    'no-new': 'error',

    // disallow use of new operator for Function object
    'no-new-func': 'error',

    // disallows creating new instances of String, Number, and Boolean
    'no-new-wrappers': 'error',

    // disallow use of (old style) octal literals
    'no-octal': 'error',

    // disallow use of octal escape sequences in string literals, such as
    // var foo = 'Copyright \251';
    'no-octal-escape': 'error',

    // disallow reassignment of function parameters
    // disallow parameter object manipulation except for specific exclusions
    // rule: http://eslint.org/docs/rules/no-param-reassign.html
    'no-param-reassign': ['error', {
      props: true,
      ignorePropertyModificationsFor: [
        'acc', // for reduce accumulators
        'e', // for e.returnvalue
        'ctx', // for Koa routing
        'req', // for Express requests
        'request', // for Express requests
        'res', // for Express responses
        'response', // for Express responses
        '$scope', // for Angular 1 scopes
      ],
    }],

    // disallow usage of __proto__ property
    'no-proto': 'error',

    // disallow declaring the same variable more then once
    'no-redeclare': 'error',

    // disallow certain object properties
    // http://eslint.org/docs/rules/no-restricted-properties
    'no-restricted-properties': ['error', {
      object: 'arguments',
      property: 'callee',
      message: 'arguments.callee is deprecated',
    }, {
      object: 'global',
      property: 'isFinite',
      message: 'Please use Number.isFinite instead',
    }, {
      object: 'self',
      property: 'isFinite',
      message: 'Please use Number.isFinite instead',
    }, {
      object: 'window',
      property: 'isFinite',
      message: 'Please use Number.isFinite instead',
    }, {
      object: 'global',
      property: 'isNaN',
      message: 'Please use Number.isNaN instead',
    }, {
      object: 'self',
      property: 'isNaN',
      message: 'Please use Number.isNaN instead',
    }, {
      object: 'window',
      property: 'isNaN',
      message: 'Please use Number.isNaN instead',
    }, {
      property: '__defineGetter__',
      message: 'Please use Object.defineProperty instead.',
    }, {
      property: '__defineSetter__',
      message: 'Please use Object.defineProperty instead.',
    }, {
      object: 'Math',
      property: 'pow',
      message: 'Use the exponentiation operator (**) instead.',
    }],

    // disallow use of assignment in return statement
    'no-return-assign': ['error', 'always'],

    // disallow redundant `return await`
    'no-return-await': 'error',

    // disallow use of `javascript:` urls.
    'no-script-url': 'error',

    // disallow self assignment
    // http://eslint.org/docs/rules/no-self-assign
    'no-self-assign': 'error',

    // disallow comparisons where both sides are exactly the same
    'no-self-compare': 'error',

    // disallow use of comma operator
    'no-sequences': 'error',

    // restrict what can be thrown as an exception
    'no-throw-literal': 'error',

    // disallow unmodified conditions of loops
    // http://eslint.org/docs/rules/no-unmodified-loop-condition
    'no-unmodified-loop-condition': 'off',

    // disallow usage of expressions in statement position
    'no-unused-expressions': ['error', {
      allowShortCircuit: false,
      allowTernary: false,
      allowTaggedTemplates: false,
    }],

    // disallow unused labels
    // http://eslint.org/docs/rules/no-unused-labels
    'no-unused-labels': 'error',

    // disallow unnecessary .call() and .apply()
    'no-useless-call': 'off',

    // disallow useless string concatenation
    // http://eslint.org/docs/rules/no-useless-concat
    'no-useless-concat': 'error',

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

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

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

    // disallow usage of configurable warning terms in comments: e.g. todo
    'no-warning-comments': ['off', { terms: ['todo', 'fixme', 'xxx'], location: 'start' }],

    // disallow use of the with statement
    'no-with': 'error',

    // require using Error objects as Promise rejection reasons
    // http://eslint.org/docs/rules/prefer-promise-reject-errors
    'prefer-promise-reject-errors': ['error', { allowEmptyReject: true }],

    // require use of the second argument for parseInt()
    radix: 'error',

    // require `await` in `async function` (note: this is a horrible rule that should never be used)
    // http://eslint.org/docs/rules/require-await
    'require-await': 'off',

    // requires to declare all vars on top of their containing scope
    'vars-on-top': 'error',

    // require immediate function invocation to be wrapped in parentheses
    // http://eslint.org/docs/rules/wrap-iife.html
    'wrap-iife': ['error', 'outside', { functionPrototypeMethods: false }],

    // require or disallow Yoda conditions
    yoda: 'error',


    // Enforce “for” loop update clause moving the counter in the right direction
    // http://eslint.org/docs/rules/for-direction
    'for-direction': 'error',

    // Enforces that a return statement is present in property getters
    // http://eslint.org/docs/rules/getter-return
    'getter-return': ['error', { allowImplicit: true }],

    // Disallow await inside of loops
    // http://eslint.org/docs/rules/no-await-in-loop
    'no-await-in-loop': 'error',

    // Disallow comparisons to negative zero
    // http://eslint.org/docs/rules/no-compare-neg-zero
    'no-compare-neg-zero': 'error',

    // disallow assignment in conditional expressions
    'no-cond-assign': ['error', 'always'],

    // disallow use of console
    'no-console': 'warn',

    // disallow use of constant expressions in conditions
    'no-constant-condition': 'warn',

    // disallow control characters in regular expressions
    'no-control-regex': 'error',

    // disallow use of debugger
    'no-debugger': 'error',

    // disallow duplicate arguments in functions
    'no-dupe-args': 'error',

    // disallow duplicate keys when creating object literals
    'no-dupe-keys': 'error',

    // disallow a duplicate case label.
    'no-duplicate-case': 'error',

    // disallow empty statements
    'no-empty': 'error',

    // disallow the use of empty character classes in regular expressions
    'no-empty-character-class': 'error',

    // disallow assigning to the exception in a catch block
    'no-ex-assign': 'error',

    // disallow double-negation boolean casts in a boolean context
    // http://eslint.org/docs/rules/no-extra-boolean-cast
    'no-extra-boolean-cast': 'error',

    // disallow unnecessary parentheses
    // http://eslint.org/docs/rules/no-extra-parens
    'no-extra-parens': ['off', 'all', {
      conditionalAssign: true,
      nestedBinaryExpressions: false,
      returnAssign: false,
      ignoreJSX: 'all', // delegate to eslint-plugin-react
      enforceForArrowConditionals: false,
    }],

    // disallow unnecessary semicolons
    'no-extra-semi': 'error',

    // disallow overwriting functions written as function declarations
    'no-func-assign': 'error',

    // disallow function or variable declarations in nested blocks
    'no-inner-declarations': 'error',

    // disallow invalid regular expression strings in the RegExp constructor
    'no-invalid-regexp': 'error',

    // disallow irregular whitespace outside of strings and comments
    'no-irregular-whitespace': 'error',

    // disallow the use of object properties of the global object (Math and JSON) as functions
    'no-obj-calls': 'error',

    // disallow use of Object.prototypes builtins directly
    // http://eslint.org/docs/rules/no-prototype-builtins
    'no-prototype-builtins': 'error',

    // disallow multiple spaces in a regular expression literal
    'no-regex-spaces': 'error',

    // disallow sparse arrays
    'no-sparse-arrays': 'error',

    // Disallow template literal placeholder syntax in regular strings
    // http://eslint.org/docs/rules/no-template-curly-in-string
    'no-template-curly-in-string': 'error',

    // Avoid code that looks like two expressions but is actually one
    // http://eslint.org/docs/rules/no-unexpected-multiline
    'no-unexpected-multiline': 'error',

    // disallow unreachable statements after a return, throw, continue, or break statement
    'no-unreachable': 'error',

    // disallow return/throw/break/continue inside finally blocks
    // http://eslint.org/docs/rules/no-unsafe-finally
    'no-unsafe-finally': 'error',

    // disallow negating the left operand of relational operators
    // http://eslint.org/docs/rules/no-unsafe-negation
    'no-unsafe-negation': 'error',
    // disallow negation of the left operand of an in expression
    // deprecated in favor of no-unsafe-negation
    'no-negated-in-lhs': 'off',

    // disallow comparisons with the value NaN
    'use-isnan': 'error',

    // ensure JSDoc comments are valid
    // http://eslint.org/docs/rules/valid-jsdoc
    'valid-jsdoc': 'off',

    // ensure that the results of typeof are compared against a valid string
    // http://eslint.org/docs/rules/valid-typeof
    'valid-typeof': ['error', { requireStringLiterals: true }],


    // enforces no braces where they can be omitted
    // http://eslint.org/docs/rules/arrow-body-style
    // TODO: enable requireReturnForObjectLiteral?
    'arrow-body-style': ['error', 'as-needed', {
      requireReturnForObjectLiteral: false,
    }],

    // require parens in arrow function arguments
    // http://eslint.org/docs/rules/arrow-parens
    'arrow-parens': ['error', 'as-needed', {
      requireForBlockBody: true,
    }],

    // require space before/after arrow function's arrow
    // http://eslint.org/docs/rules/arrow-spacing
    'arrow-spacing': ['error', { before: true, after: true }],

    // verify super() callings in constructors
    'constructor-super': 'error',

    // enforce the spacing around the * in generator functions
    // http://eslint.org/docs/rules/generator-star-spacing
    'generator-star-spacing': ['error', { before: false, after: true }],

    // disallow modifying variables of class declarations
    // http://eslint.org/docs/rules/no-class-assign
    'no-class-assign': 'error',

    // disallow arrow functions where they could be confused with comparisons
    // http://eslint.org/docs/rules/no-confusing-arrow
    'no-confusing-arrow': ['error', {
      allowParens: true,
    }],

    // disallow modifying variables that are declared using const
    'no-const-assign': 'error',

    // disallow duplicate class members
    // http://eslint.org/docs/rules/no-dupe-class-members
    'no-dupe-class-members': 'error',

    // disallow importing from the same path more than once
    // http://eslint.org/docs/rules/no-duplicate-imports
    // replaced by https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-duplicates.md
    'no-duplicate-imports': 'off',

    // disallow symbol constructor
    // http://eslint.org/docs/rules/no-new-symbol
    'no-new-symbol': 'error',

    // disallow specific imports
    // http://eslint.org/docs/rules/no-restricted-imports
    'no-restricted-imports': 'off',

    // disallow to use this/super before super() calling in constructors.
    // http://eslint.org/docs/rules/no-this-before-super
    'no-this-before-super': 'error',

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

    // disallow unnecessary constructor
    // http://eslint.org/docs/rules/no-useless-constructor
    'no-useless-constructor': 'error',

    // disallow renaming import, export, and destructured assignments to the same name
    // http://eslint.org/docs/rules/no-useless-rename
    'no-useless-rename': ['error', {
      ignoreDestructuring: false,
      ignoreImport: false,
      ignoreExport: false,
    }],

    // require let or const instead of var
    'no-var': 'error',

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

    // suggest using arrow functions as callbacks
    'prefer-arrow-callback': ['error', {
      allowNamedFunctions: false,
      allowUnboundThis: true,
    }],

    // suggest using of const declaration for variables that are never modified after declared
    'prefer-const': ['error', {
      destructuring: 'any',
      ignoreReadBeforeAssign: true,
    }],

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

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

    // suggest using Reflect methods where applicable
    // http://eslint.org/docs/rules/prefer-reflect
    'prefer-reflect': 'off',

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

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

    // suggest using template literals instead of string concatenation
    // http://eslint.org/docs/rules/prefer-template
    'prefer-template': 'error',

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

    // enforce spacing between object rest-spread
    // http://eslint.org/docs/rules/rest-spread-spacing
    'rest-spread-spacing': ['error', 'never'],

    // import sorting
    // http://eslint.org/docs/rules/sort-imports
    'sort-imports': ['off', {
      ignoreCase: false,
      ignoreMemberSort: false,
      memberSyntaxSortOrder: ['none', 'all', 'multiple', 'single'],
    }],

    // require a Symbol description
    // http://eslint.org/docs/rules/symbol-description
    'symbol-description': 'error',

    // enforce usage of spacing in template strings
    // http://eslint.org/docs/rules/template-curly-spacing
    'template-curly-spacing': 'error',

    // enforce spacing around the * in yield* expressions
    // http://eslint.org/docs/rules/yield-star-spacing
    'yield-star-spacing': ['error', 'after'],


    // enforce return after a callback
    'callback-return': 'off',

    // require all requires be top-level
    // http://eslint.org/docs/rules/global-require
    'global-require': 'error',

    // enforces error handling in callbacks (node environment)
    'handle-callback-err': 'off',

    // disallow use of the Buffer() constructor
    // http://eslint.org/docs/rules/no-buffer-constructor
    'no-buffer-constructor': 'error',

    // disallow mixing regular variable and require declarations
    'no-mixed-requires': ['off', false],

    // disallow use of new operator with the require function
    'no-new-require': 'error',

    // disallow string concatenation with __dirname and __filename
    // http://eslint.org/docs/rules/no-path-concat
    'no-path-concat': 'error',

    // disallow use of process.env
    'no-process-env': 'off',

    // disallow process.exit()
    'no-process-exit': 'off',

    // restrict usage of specified node modules
    'no-restricted-modules': 'off',

    // disallow use of synchronous methods (off by default)
    'no-sync': 'off',

    // enforce line breaks after opening and before closing array brackets
    // http://eslint.org/docs/rules/array-bracket-newline
    // TODO: enable? semver-major
    'array-bracket-newline': ['off', 'consistent'], // object option alternative: { multiline: true, minItems: 3 }

    // enforce line breaks between array elements
    // http://eslint.org/docs/rules/array-element-newline
    // TODO: enable? semver-major
    'array-element-newline': ['off', { multiline: true, minItems: 3 }],

    // enforce spacing inside array brackets
    'array-bracket-spacing': ['error', 'never'],

    // enforce spacing inside single-line blocks
    // http://eslint.org/docs/rules/block-spacing
    'block-spacing': ['error', 'always'],

    // enforce one true brace style
    'brace-style': ['error', '1tbs', { allowSingleLine: true }],

    // require camel case names
    camelcase: ['error', { properties: 'never' }],

    // enforce or disallow capitalization of the first letter of a comment
    // http://eslint.org/docs/rules/capitalized-comments
    'capitalized-comments': ['off', 'never', {
      line: {
        ignorePattern: '.*',
        ignoreInlineComments: true,
        ignoreConsecutiveComments: true,
      },
      block: {
        ignorePattern: '.*',
        ignoreInlineComments: true,
        ignoreConsecutiveComments: true,
      },
    }],

    // require trailing commas in multiline object literals
    'comma-dangle': ['error', {
      arrays: 'always-multiline',
      objects: 'always-multiline',
      imports: 'always-multiline',
      exports: 'always-multiline',
      functions: 'always-multiline',
    }],

    // enforce spacing before and after comma
    'comma-spacing': ['error', { before: false, after: true }],

    // enforce one true comma style
    'comma-style': ['error', 'last'],

    // disallow padding inside computed properties
    'computed-property-spacing': ['error', 'never'],

    // enforces consistent naming when capturing the current execution context
    'consistent-this': 'off',

    // enforce newline at the end of file, with no multiple empty lines
    'eol-last': ['error', 'always'],

    // enforce spacing between functions and their invocations
    // http://eslint.org/docs/rules/func-call-spacing
    'func-call-spacing': ['error', 'never'],

    // requires function names to match the name of the variable or property to which they are
    // assigned
    // http://eslint.org/docs/rules/func-name-matching
    'func-name-matching': ['off', 'always', {
      includeCommonJSModuleExports: false,
    }],

    // require function expressions to have a name
    // http://eslint.org/docs/rules/func-names
    // TODO: only Uchi.ru
    'func-names': ['warn', 'never'],

    // enforces use of function declarations or expressions
    // http://eslint.org/docs/rules/func-style
    // TODO: enable
    'func-style': ['off', 'expression'],

    // enforce consistent line breaks inside function parentheses
    // https://eslint.org/docs/rules/function-paren-newline
    'function-paren-newline': ['error', 'multiline'],

    // Blacklist certain identifiers to prevent them being used
    // http://eslint.org/docs/rules/id-blacklist
    'id-blacklist': 'off',

    // this option enforces minimum and maximum identifier lengths
    // (variable names, property names etc.)
    'id-length': 'off',

    // require identifiers to match the provided regular expression
    'id-match': 'off',

    // this option sets a specific tab width for your code
    // http://eslint.org/docs/rules/indent
    indent: ['error', 2, {
      SwitchCase: 1,
      VariableDeclarator: 1,
      outerIIFEBody: 1,
      // MemberExpression: null,
      FunctionDeclaration: {
        parameters: 1,
        body: 1,
      },
      FunctionExpression: {
        parameters: 1,
        body: 1,
      },
      CallExpression: {
        arguments: 1,
      },
      ArrayExpression: 1,
      ObjectExpression: 1,
      ImportDeclaration: 1,
      flatTernaryExpressions: false,
      ignoredNodes: ['JSXElement', 'JSXElement *'],
    }],

    // specify whether double or single quotes should be used in JSX attributes
    // http://eslint.org/docs/rules/jsx-quotes
    'jsx-quotes': ['off', 'prefer-double'],

    // enforces spacing between keys and values in object literal properties
    'key-spacing': ['error', { beforeColon: false, afterColon: true }],

    // require a space before & after certain keywords
    'keyword-spacing': ['error', {
      before: true,
      after: true,
      overrides: {
        return: { after: true },
        throw: { after: true },
        case: { after: true },
      },
    }],

    // enforce position of line comments
    // http://eslint.org/docs/rules/line-comment-position
    // TODO: enable?
    'line-comment-position': ['off', {
      position: 'above',
      ignorePattern: '',
      applyDefaultPatterns: true,
    }],

    // disallow mixed 'LF' and 'CRLF' as linebreaks
    // http://eslint.org/docs/rules/linebreak-style
    'linebreak-style': ['error', 'unix'],

    // require or disallow an empty line between class members
    // https://eslint.org/docs/rules/lines-between-class-members
    // TODO: semver-major: enable
    'lines-between-class-members': ['off', 'always', { exceptAfterSingleLine: false }],

    // enforces empty lines around comments
    'lines-around-comment': 'off',

    // require or disallow newlines around directives
    // http://eslint.org/docs/rules/lines-around-directive
    'lines-around-directive': ['error', {
      before: 'always',
      after: 'always',
    }],

    // specify the maximum depth that blocks can be nested
    'max-depth': ['off', 4],

    // specify the maximum length of a line in your program
    // http://eslint.org/docs/rules/max-len
    'max-len': ['error', 100, 2, {
      ignoreUrls: true,
      ignoreComments: false,
      ignoreRegExpLiterals: true,
      ignoreStrings: true,
      ignoreTemplateLiterals: true,
    }],

    // specify the max number of lines in a file
    // http://eslint.org/docs/rules/max-lines
    'max-lines': ['off', {
      max: 300,
      skipBlankLines: true,
      skipComments: true,
    }],

    // specify the maximum depth callbacks can be nested
    'max-nested-callbacks': 'off',

    // limits the number of parameters that can be used in the function declaration.
    'max-params': ['off', 3],

    // specify the maximum number of statement allowed in a function
    'max-statements': ['off', 10],

    // restrict the number of statements per line
    // http://eslint.org/docs/rules/max-statements-per-line
    'max-statements-per-line': ['off', { max: 1 }],

    // enforce a particular style for multiline comments
    // https://eslint.org/docs/rules/multiline-comment-style
    'multiline-comment-style': ['off', 'starred-block'],

    // require multiline ternary
    // http://eslint.org/docs/rules/multiline-ternary
    // TODO: enable?
    'multiline-ternary': ['off', 'never'],

    // require a capital letter for constructors
    'new-cap': ['error', {
      newIsCap: true,
      newIsCapExceptions: [],
      capIsNew: false,
      capIsNewExceptions: ['Immutable.Map', 'Immutable.Set', 'Immutable.List'],
    }],

    // disallow the omission of parentheses when invoking a constructor with no arguments
    // http://eslint.org/docs/rules/new-parens
    'new-parens': 'error',

    // allow/disallow an empty newline after var statement
    'newline-after-var': 'off',

    // http://eslint.org/docs/rules/newline-before-return
    'newline-before-return': 'off',

    // enforces new line after each method call in the chain to make it
    // more readable and easy to maintain
    // http://eslint.org/docs/rules/newline-per-chained-call
    'newline-per-chained-call': ['error', { ignoreChainWithDepth: 4 }],

    // disallow use of the Array constructor
    'no-array-constructor': 'error',

    // disallow use of bitwise operators
    // http://eslint.org/docs/rules/no-bitwise
    'no-bitwise': 'error',

    // disallow use of the continue statement
    // http://eslint.org/docs/rules/no-continue
    'no-continue': 'error',

    // disallow comments inline after code
    'no-inline-comments': 'off',

    // disallow if as the only statement in an else block
    // http://eslint.org/docs/rules/no-lonely-if
    'no-lonely-if': 'error',

    // disallow un-paren'd mixes of different operators
    // http://eslint.org/docs/rules/no-mixed-operators
    'no-mixed-operators': ['error', {
      groups: [
        ['+', '-', '*', '/', '%', '**'],
        ['&', '|', '^', '~', '<<', '>>', '>>>'],
        ['==', '!=', '===', '!==', '>', '>=', '<', '<='],
        ['&&', '||'],
        ['in', 'instanceof'],
      ],
      allowSamePrecedence: false,
    }],

    // disallow mixed spaces and tabs for indentation
    'no-mixed-spaces-and-tabs': 'error',

    // disallow use of chained assignment expressions
    // http://eslint.org/docs/rules/no-multi-assign
    'no-multi-assign': ['error'],

    // disallow multiple empty lines and only one newline at the end
    'no-multiple-empty-lines': ['error', { max: 2, maxEOF: 1 }],

    // disallow negated conditions
    // http://eslint.org/docs/rules/no-negated-condition
    'no-negated-condition': 'off',

    // disallow nested ternary expressions
    'no-nested-ternary': 'error',

    // disallow use of the Object constructor
    'no-new-object': 'error',

    // disallow use of unary operators, ++ and --
    // http://eslint.org/docs/rules/no-plusplus
    'no-plusplus': ['error', { allowForLoopAfterthoughts: true }],

    // disallow certain syntax forms
    // http://eslint.org/docs/rules/no-restricted-syntax
    'no-restricted-syntax': [
      'error',
      {
        selector: 'ForInStatement',
        message: 'for..in loops iterate over the entire prototype chain, which is virtually never what you want. Use Object.{keys,values,entries}, and iterate over the resulting array.',
      },
      {
        selector: 'ForOfStatement',
        message: 'iterators/generators require regenerator-runtime, which is too heavyweight for this guide to allow them. Separately, loops should be avoided in favor of array iterations.',
      },
      {
        selector: 'LabeledStatement',
        message: 'Labels are a form of GOTO; using them makes code confusing and hard to maintain and understand.',
      },
      {
        selector: 'WithStatement',
        message: '`with` is disallowed in strict mode because it makes code impossible to predict and optimize.',
      },
    ],

    // disallow space between function identifier and application
    'no-spaced-func': 'error',

    // disallow tab characters entirely
    'no-tabs': 'error',

    // disallow the use of ternary operators
    'no-ternary': 'off',

    // disallow trailing whitespace at the end of lines
    'no-trailing-spaces': ['error', {
      skipBlankLines: false,
      ignoreComments: false,
    }],

    // disallow dangling underscores in identifiers
    'no-underscore-dangle': ['error', {
      allow: [],
      allowAfterThis: false,
      allowAfterSuper: false,
      enforceInMethodNames: false,
    }],

    // disallow the use of Boolean literals in conditional expressions
    // also, prefer `a || b` over `a ? a : b`
    // http://eslint.org/docs/rules/no-unneeded-ternary
    'no-unneeded-ternary': ['error', { defaultAssignment: false }],

    // disallow whitespace before properties
    // http://eslint.org/docs/rules/no-whitespace-before-property
    'no-whitespace-before-property': 'error',

    // enforce the location of single-line statements
    // http://eslint.org/docs/rules/nonblock-statement-body-position
    'nonblock-statement-body-position': 'off',

    // require padding inside curly braces
    'object-curly-spacing': ['error', 'always'],

    // enforce line breaks between braces
    // http://eslint.org/docs/rules/object-curly-newline
    'object-curly-newline': ['error', {
      ObjectExpression: { minProperties: 4, multiline: true, consistent: true },
      ObjectPattern: { minProperties: 4, multiline: true, consistent: true },
    }],

    // enforce "same line" or "multiple line" on object properties.
    // http://eslint.org/docs/rules/object-property-newline
    'object-property-newline': ['error', {
      allowMultiplePropertiesPerLine: true,
    }],

    // allow just one var statement per function
    'one-var': ['error', 'never'],

    // require a newline around variable declaration
    // http://eslint.org/docs/rules/one-var-declaration-per-line
    'one-var-declaration-per-line': ['error', 'always'],

    // require assignment operator shorthand where possible or prohibit it entirely
    // http://eslint.org/docs/rules/operator-assignment
    'operator-assignment': ['error', 'always'],

    // enforce operators to be placed before or after line breaks
    'operator-linebreak': 'off',

    // disallow padding within blocks
    'padded-blocks': ['error', { blocks: 'never', classes: 'never', switches: 'never' }],

    // Require or disallow padding lines between statements
    // http://eslint.org/docs/rules/padding-line-between-statements
    'padding-line-between-statements': 'off',

    // require quotes around object literal property names
    // http://eslint.org/docs/rules/quote-props.html
    'quote-props': ['error', 'as-needed', { keywords: false, unnecessary: true, numbers: false }],

    // specify whether double or single quotes should be used
    quotes: ['error', 'single', { avoidEscape: true }],

    // do not require jsdoc
    // http://eslint.org/docs/rules/require-jsdoc
    'require-jsdoc': 'off',

    // require or disallow use of semicolons instead of ASI
    semi: ['error', 'always'],

    // enforce spacing before and after semicolons
    'semi-spacing': ['error', { before: false, after: true }],

    // Enforce location of semicolons
    // http://eslint.org/docs/rules/semi-style
    'semi-style': ['error', 'last'],

    // requires object keys to be sorted
    'sort-keys': ['off', 'asc', { caseSensitive: false, natural: true }],

    // sort variables within the same declaration block
    'sort-vars': 'off',

    // require or disallow space before blocks
    'space-before-blocks': 'error',

    // require or disallow space before function opening parenthesis
    // http://eslint.org/docs/rules/space-before-function-paren
    'space-before-function-paren': ['error', {
      anonymous: 'always',
      named: 'never',
      asyncArrow: 'always',
    }],

    // require or disallow spaces inside parentheses
    'space-in-parens': ['error', 'never'],

    // require spaces around operators
    'space-infix-ops': 'error',

    // Require or disallow spaces before/after unary operators
    // http://eslint.org/docs/rules/space-unary-ops
    'space-unary-ops': ['error', {
      words: true,
      nonwords: false,
      overrides: {
      },
    }],

    // require or disallow a space immediately following the // or /* in a comment
    // http://eslint.org/docs/rules/spaced-comment
    'spaced-comment': ['error', 'always', {
      line: {
        exceptions: ['-', '+'],
        markers: ['=', '!'], // space here to support sprockets directives
      },
      block: {
        exceptions: ['-', '+'],
        markers: ['=', '!'], // space here to support sprockets directives
        balanced: true,
      },
    }],

    // Enforce spacing around colons of switch statements
    // http://eslint.org/docs/rules/switch-colon-spacing
    'switch-colon-spacing': ['error', { after: true, before: false }],

    // Require or disallow spacing between template tags and their literals
    // http://eslint.org/docs/rules/template-tag-spacing
    'template-tag-spacing': ['error', 'never'],

    // require or disallow the Unicode Byte Order Mark
    // http://eslint.org/docs/rules/unicode-bom
    'unicode-bom': ['error', 'never'],

    // require regex literals to be wrapped in parentheses
    'wrap-regex': 'off',

    // enforce or disallow variable initializations at definition
    'init-declarations': 'off',

    // disallow the catch clause parameter name being the same as a variable in the outer scope
    'no-catch-shadow': 'off',

    // disallow deletion of variables
    'no-delete-var': 'error',

    // disallow labels that share a name with a variable
    // http://eslint.org/docs/rules/no-label-var
    'no-label-var': 'error',

    // disallow specific globals
    'no-restricted-globals': ['error', 'isFinite', 'isNaN'].concat(restrictedGlobals),

    // disallow declaration of variables already declared in the outer scope
    'no-shadow': 'error',

    // disallow shadowing of names such as arguments
    'no-shadow-restricted-names': 'error',

    // disallow use of undeclared variables unless mentioned in a /*global */ block
    'no-undef': 'error',

    // disallow use of undefined when initializing variables
    'no-undef-init': 'error',

    // disallow use of undefined variable
    // http://eslint.org/docs/rules/no-undefined
    // TODO: enable?
    'no-undefined': 'off',

    // disallow declaration of variables that are not used in the code
    'no-unused-vars': ['error', { vars: 'all', args: 'after-used', ignoreRestSiblings: true }],

    // disallow use of variables before they are defined
    'no-use-before-define': ['error', { functions: true, classes: true, variables: true }],
  },
};