.eslintrc.yaml

# http://eslint.org/docs/rules/ - Disallow everything (documents what is not used) with 0. If not 0, rule is enabled (moved up).

env:
  browser: true  # browser global variables.
  es6: true      # enable all ECMAScript 6 features except for modules.
  jquery: true   # jQuery global variables.

  node: false           # Node.js global variables and Node.js scoping.
  commonjs: false       # CommonJS global variables and CommonJS scoping (use this for browser-only code that uses Browserify/WebPack).
  worker: false         # web workers global variables.
  amd: false            # defines require() and define() as global variables as per the amd spec.
  mocha: false          # adds all of the Mocha testing global variables.
  jasmine: false        # adds all of the Jasmine testing global variables for version 1.3 and 2.0.
  jest: false           # Jest global variables.
  phantomjs: false      # PhantomJS global variables.
  protractor: false     # Protractor global variables.
  qunit: false          # QUnit global variables.
  prototypejs: false    # Prototype.js global variables.
  shelljs: false        # ShellJS global variables.
  meteor: false         # Meteor global variables.
  mongo: false          # MongoDB global variables.
  applescript: false    # AppleScript global variables.
  nashorn: false        # Java 8 Nashorn global variables.
  serviceworker: false  # Service Worker global variables.
  embertest: false      # Ember test helper globals.
  webextensions: false  # WebExtensions globals.

globals: # false means: read-only
  _: false       # Lodash (or Underscore)
  mobx: false    # https://github.com/mobxjs/mobx/
  moment: false  # Moment.js

parserOptions:
  ecmaVersion: 6
  sourceType: module

rules:

  # Style #

  indent:                       # specify tab or space width for your code (fixable)
    - 2
    - tab
  no-mixed-spaces-and-tabs: 2   # disallow mixed spaces and tabs for indentation (recommended)
  linebreak-style:              # disallow mixed 'LF' and 'CRLF' as linebreaks
    - 2
    - unix
  eol-last: 1                   # enforce newline at the end of file, with no multiple empty lines (fixable)
  semi:                         # require or disallow use of semicolons instead of ASI (fixable)
    - 2
    - always
  comma-spacing:                # enforce spacing before and after comma
    - 1
    -
      before: false
      after: true
  key-spacing:                  # enforce spacing between keys and values in object literal properties
    - 1
    -
      beforeColon: false
      afterColon: true
      mode: minimum
  brace-style:                  # enforce brace style
    - 1
    - allman
    - allowSingleLine: true # See https://github.com/eslint/eslint/issues/5197
  block-spacing:                # disallow or enforce spaces inside of single line blocks (fixable)
    - 1
    - always
  padded-blocks:                # enforce padding within blocks
    - 1
    - never
  no-irregular-whitespace: 1    # disallow irregular whitespace outside of strings and comments
  no-trailing-spaces: 1         # disallow trailing whitespace at the end of lines (fixable)
  keyword-spacing: 1            # enforce spacing before and after keywords (fixable)
  space-before-blocks: 1        # require or disallow a space before blocks (fixable)
  space-before-function-paren:  # require or disallow a space before function opening parenthesis (fixable)
    - 1
    -
      anonymous: always
      named: never
  space-in-parens:              # require or disallow spaces inside parentheses
    - 1
    - never
  object-curly-spacing:         # require or disallow padding inside curly braces (fixable)
    - 1
    - always
  array-bracket-spacing:        # enforce spacing inside array brackets (fixable)
    - 1
    - always
  space-infix-ops: 1            # require spaces around operators (fixable)
  spaced-comment: 1             # require or disallow a space immediately following the # or /* in a comment
  max-depth:                    # specify the maximum depth that blocks can be nested
    - 1
    - 5
  max-len:                      # specify the maximum length of a line in your program
    - 1
    - 120
  max-params:                   # limits the number of parameters that can be used in the function declaration
    - 1
    - 5
  max-statements:               # specify the maximum number of statement allowed in a function
    - 1
    - 42

  new-cap: 2                    # require a capital letter for constructors
  new-parens: 2                 # disallow the omission of parentheses when invoking a constructor with no arguments

  camelcase: 0                  # require camel case names
  comma-style: 0                # enforce one true comma style
  computed-property-spacing: 0  # require or disallow padding inside computed properties (fixable)
  consistent-this: 0            # enforce consistent naming when capturing the current execution context
  func-names: 0                 # require function expressions to have a name
  func-style: 0                 # enforce use of function declarations or expressions
  id-length: 0                  # this option enforces minimum and maximum identifier lengths (variable names, property names etc.)
  id-match: 0                   # require identifiers to match the provided regular expression
  jsx-quotes: 0                 # specify whether double or single quotes should be used in JSX attributes
  lines-around-comment: 0       # enforce empty lines around comments
  max-nested-callbacks: 0       # specify the maximum depth callbacks can be nested
  no-array-constructor: 0       # disallow use of the Array constructor
  newline-after-var: 0          # require or disallow an empty newline after variable declarations
  no-bitwise: 0                 # disallow use of bitwise operators
  no-continue: 0                # disallow use of the continue statement
  no-inline-comments: 0         # disallow comments inline after code
  no-lonely-if: 0               # disallow if as the only statement in an else block
  no-multiple-empty-lines: 0    # disallow multiple empty lines
  no-nested-ternary: 0          # disallow nested ternary expressions
  no-negated-condition: 0       # disallow negated conditions
  no-new-object: 0              # disallow the use of the Object constructor
  no-plusplus: 0                # disallow use of unary operators, ++ and --
  no-restricted-syntax: 0       # disallow use of certain syntax in code
  no-spaced-func: 0             # disallow space between function identifier and application (fixable)
  no-ternary: 0                 # disallow the use of ternary operators
  no-underscore-dangle: 0       # disallow dangling underscores in identifiers
  no-unneeded-ternary: 0        # disallow the use of ternary operators when a simpler alternative exists
  one-var: 0                    # require or disallow one variable declaration per function
  operator-assignment: 0        # require assignment operator shorthand where possible or prohibit it entirely
  operator-linebreak: 0         # enforce operators to be placed before or after line breaks
  quotes: 0                     # specify whether backticks, double or single quotes should be used (fixable)
  quote-props: 0                # require quotes around object literal property names
  require-jsdoc: 0              # Require JSDoc comment
  semi-spacing: 0               # enforce spacing before and after semicolons
  sort-vars: 0                  # sort variables within the same declaration block
  space-unary-ops: 0            # require or disallow spaces before/after unary operators (fixable)
  wrap-regex: 0                 # require regex literals to be wrapped in parentheses

  # Possible errors #

  no-cond-assign: 2             # disallow assignment in conditional expressions
  no-dupe-args: 2               # disallow duplicate arguments in functions
  no-dupe-keys: 2               # disallow duplicate keys when creating object literals
  no-duplicate-case: 2          # disallow a duplicate case label
  no-extra-parens: 0            # disallow unnecessary parentheses (off by default)
  no-extra-semi: 1              # disallow unnecessary semicolons
  no-func-assign: 2             # disallow overwriting functions written as function declarations
  no-unreachable: 2             # disallow unreachable statements after a return, throw, continue, or break statement
  use-isnan: 2                  # disallow comparisons with the value NaN
  valid-typeof: 2               # Ensure that the results of typeof are compared against a valid string

  no-empty-character-class: 2   # disallow the use of empty character classes in regular expressions
  no-invalid-regexp: 2          # disallow invalid regular expression strings in the RegExp constructor

  comma-dangle: 0               # disallow trailing commas in object literals
  no-console: 0                 # disallow use of console (off by default in the node environment)
  no-constant-condition: 0      # disallow use of constant expressions in conditions
  no-control-regex: 0           # disallow control characters in regular expressions
  no-debugger: 0                # disallow use of debugger
  no-empty: 0                   # disallow empty statements
  no-ex-assign: 0               # disallow assigning to the exception in a catch block
  no-extra-boolean-cast: 0      # disallow double-negation boolean casts in a boolean context
  no-inner-declarations: 0      # disallow function or variable declarations in nested blocks
  no-negated-in-lhs: 0          # disallow negation of the left operand of an in expression
  no-obj-calls: 0               # disallow the use of object properties of the global object (Math and JSON) as functions
  no-regex-spaces: 0            # disallow multiple spaces in a regular expression literal
  no-sparse-arrays: 0           # disallow sparse arrays
  valid-jsdoc: 0                # Ensure JSDoc comments are valid (off by default)
  no-unexpected-multiline: 0    # Avoid code that looks like two expressions but is actually one (off by default)

  # Best practices #

  curly: 0                  # specify curly brace conventions for all control statements
  eqeqeq:                   # require the use of === and !==
    - 2
    - smart
  no-case-declarations: 2   # disallow lexical declarations in case clauses
  no-else-return: 2         # disallow else after a return in an if (off by default)
  no-floating-decimal: 1    # disallow the use of leading or trailing decimal points in numeric literals (off by default)
  no-invalid-this: 2        # disallow this keywords outside of classes or class-like objects
  no-octal-escape: 2        # disallow use of octal escape sequences in string literals, such as var foo = "Copyright \251";
  no-octal: 2               # disallow use of octal literals
  no-redeclare: 2           # disallow declaring the same variable more than once
  no-return-assign: 2       # disallow use of assignment in return statement
  no-unused-expressions: 2  # disallow usage of expressions in statement position
  no-useless-call: 2        # disallow unnecessary .call() and .apply()
  no-useless-concat: 2      # disallow unnecessary concatenation of literals or template literals
  yoda: 1                   # require or disallow Yoda conditions

  accessor-pairs: 0         # enforces getter/setter pairs in objects (off by default)
  block-scoped-var: 0       # treat var statements as if they were block scoped (off by default)
  complexity: 0             # specify the maximum cyclomatic complexity allowed in a program (off by default)
  consistent-return: 0      # require return statements to either always or never specify values
  default-case: 0           # require default case in switch statements (off by default)
  dot-notation: 0           # encourages use of dot notation whenever possible
  dot-location: 0           # enforces consistent newlines before or after dots (off by default)
  guard-for-in: 0           # make sure for-in loops have an if statement (off by default)
  no-alert: 0               # disallow the use of alert, confirm, and prompt
  no-caller: 0              # disallow use of arguments.caller or arguments.callee
  no-div-regex: 0           # disallow division operators explicitly at beginning of regular expression (off by default)
  no-empty-label: 0         # disallow use of labels for anything other then loops and switches
  no-eq-null: 0             # disallow comparisons to null without a type-checking operator (off by default)
  no-eval: 0                # disallow use of eval()
  no-extend-native: 0       # disallow adding to native types
  no-extra-bind: 0          # disallow unnecessary function binding
  no-fallthrough: 0         # disallow fallthrough of case statements
  no-implicit-coercion: 0   # disallow the type conversions with shorter notations
  no-implied-eval: 0        # disallow use of eval()-like methods
  no-iterator: 0            # disallow usage of __iterator__ property
  no-labels: 0              # disallow use of labeled statements
  no-loop-func: 0           # disallow creation of functions within loops
  no-lone-blocks: 0         # disallow unnecessary nested blocks
  no-magic-numbers: 0       # disallow the use of magic numbers
  no-multi-spaces: 0        # disallow use of multiple spaces
  no-multi-str: 0           # disallow use of multiline strings
  no-native-reassign: 0     # disallow reassignments of native objects
  no-new-func: 0            # disallow use of new operator for Function object
  no-new-wrappers: 0        # disallows creating new instances of String, Number, and Boolean
  no-new: 0                 # disallow use of new operator when not part of the assignment or comparison
  no-param-reassign: 0      # disallow reassignment of function parameters (off by default)
  no-process-env: 0         # disallow use of process.env (off by default)
  no-proto: 0               # disallow usage of __proto__ property
  no-script-url: 0          # disallow use of javascript: URLs
  no-self-compare: 0        # disallow comparisons where both sides are exactly the same (off by default)
  no-sequences: 0           # disallow use of comma operator
  no-throw-literal: 0       # restrict what can be thrown as an exception (off by default)
  no-void: 0                # disallow use of void operator (off by default)
  no-warning-comments: 0    # disallow usage of configurable warning terms in comments, e.g. TODO or FIXME (off by default)
  no-with: 0                # disallow use of the with statement
  radix: 0                  # require use of the second argument for parseInt() (off by default)
  vars-on-top: 0            # requires to declare all vars on top of their containing scope (off by default)
  wrap-iife: 0              # require immediate function invocation to be wrapped in parentheses (off by default)

  # Variables #

  no-undef: 2                    # disallow use of undeclared variables unless mentioned in a /*global */ block
  no-shadow-restricted-names: 1  # disallow shadowing of names such as arguments
  no-unused-vars:                # disallow declaration of variables that are not used in the code
    - 1
    -
      args: none
  no-undef-init: 1           # disallow use of undefined when initializing variables

  init-declarations: 0       # enforce or disallow variable initializations at definition
  no-catch-shadow: 0         # disallow the catch clause parameter name being the same as a variable in the outer scope (off by default in the node environment)
  no-delete-var: 0           # disallow deletion of variables
  no-label-var: 0            # disallow labels that share a name with a variable
  no-shadow: 0               # disallow declaration of variables already declared in the outer scope
  no-undefined: 0            # disallow use of undefined variable (off by default)
  no-use-before-define: 0    # disallow use of variables before they are defined

  # Strict Mode #

  strict: # controls location of Use Strict Directives
    - 2
    - function

  # Node.js and CommonJS #

  callback-return: 0        # enforce return after a callback
  global-require: 0         # enforce require() on top-level module scope
  handle-callback-err: 0    # enforce error handling in callbacks
  no-mixed-requires: 0      # disallow mixing regular variable and require declarations
  no-new-require: 0         # disallow use of new operator with the require function
  no-path-concat: 0         # disallow string concatenation with __dirname and __filename
  no-process-exit: 0        # disallow process.exit()
  no-restricted-modules: 0  # restrict usage of specified node modules
  no-sync: 0                # disallow use of synchronous methods

  # EcmaScript 6 #

  arrow-body-style:                # require braces in arrow function body
    - 1
    - "as-needed"
  arrow-parens:                    # require parens in arrow function arguments
    - 1
    - "as-needed"
  arrow-spacing:                   # require space before/after arrow function's arrow (fixable)
    - 1
    -
      before: true
      after: true
  constructor-super: 2             # verify calls of super() in constructors
  generator-star-spacing:          # enforce spacing around the * in generator functions (fixable)
    - 1
    - "after"
  no-class-assign: 2               # disallow modifying variables of class declarations
  no-confusing-arrow: 2            # disallow arrow functions where they could be confused with comparisons
  no-const-assign: 2               # disallow modifying variables that are declared using const
  no-dupe-class-members: 2         # disallow duplicate name in class members
  no-duplicate-imports: 2          # disallow duplicate module imports
  no-empty-pattern: 2              # disallow use of empty destructuring patterns
  no-new-symbol: 2                 # disallow new operators with the Symbol object
  no-restricted-imports: 0         # disallow specified modules when loaded by import
  no-this-before-super: 2          # disallow use of this/super before calling super() in constructors.
  #no-useless-computed-key: 2       # disallow unnecessary computed property keys in object literals
  no-useless-constructor: 2        # disallow unnecessary constructors
  no-var: 0                        # require let or const instead of var
  object-shorthand: 2              # require method and property shorthand syntax for object literals
  prefer-arrow-callback: 1         # suggest using arrow functions as callbacks
  prefer-const: 1                  # suggest using const declaration for variables that are never modified after declared
  prefer-reflect: 0                # suggest using Reflect methods where applicable
  prefer-spread: 1                 # suggest using the spread operator instead of .apply().
  prefer-template: 1               # suggest using template literals instead of strings concatenation
  require-yield: 2                 # disallow generator functions that do not have yield
  sort-imports: 0                  # enforce sorted import declarations within modules
  template-curly-spacing: 0        # require or disallow spacing around embedded expressions of template strings
  yield-star-spacing: 0            # require or disallow spacing around the * in yield* expressions