.eslintrc

# http://eslint.org/docs/rules/
# =============================
# Which environments your script is designed to run in.
# Each environment brings with it a certain set of predefined global variables.
env:

  # Define globals exposed by Node.js.
  node: true

  # Define globals exposed by modern browsers.
  browser: true

  # Define globals exposed by ES6 / ES2015 EXCEPT for modules.
  es6: true

  # Define globals exposed by jQuery.
  jquery: true

# Let ESLint know about defined global variables.
globals:

  Drupal: true

  drupalSettings: true

# Inherit settings from ESLint Recommended config.
# Rules above override any rules configured here.
extends: 'eslint:recommended'

#  0 - turn the rule off
#  1 - turn the rule on as a warning (doesn't affect exit code)
#  2 - turn the rule on as an error (exit code is 1 when triggered)
rules:

  # Two space indentation.
  indent:
    - 2
    - 2
    - SwitchCase: 1

  # Prefer single quotes over double.
  quotes:
    - 2
    - single

  # Specify Unix line endings.
  linebreak-style:
    - 2
    - unix

  # Enforce using semicolons.
  semi:
    - 2
    - always

  # Enforce camelcase for variables.
  camelcase:
    - 2

  # Prohibit use of == and != in favor of === and !==.
  eqeqeq:
    - 2

  # Enforce placing 'use strict' at the top function scope
  strict:
    - 2
    - function

  # Prohibit use of a variable before it is defined.
  no-undef:
    - 1

  # Enforce line length to 80 characters
  max-len:
    - 2
    - 80
    - 2

  # Require capitalized names for constructor functions.
  new-cap:
    - 2

  # Warn when variables are defined but never used.
  no-unused-vars:
    - 1

  # Require one var declaration for each variable and
  # declare each variable on a newline.
  one-var:
    - 2
    - never

  # Enforce stroustrup style for braces.
  brace-style:
    - 2
    - stroustrup

  # Validates JSDoc comments are syntactically correct
  valid-jsdoc:
    - 2

  # Treat var as Block Scoped
  block-scoped-var:
    - 1

  # Require Following Curly Brace Conventions
  curly:
    - 2

  # Disallow Use of Alert
  no-alert:
    - 1

  # Disallow eval()
  no-eval:
    - 2

  # Disallow the type conversion with shorter notations
  no-implicit-coercion:
    - 2

  # Disallow Functions in Loops
  no-loop-func:
    - 2

  # Disallow Script URLs
  no-script-url:
    - 2

  # Disallow Use of the Comma Operator
  no-sequences:
    - 2

  # Disallow unnecessary concatenation of strings
  no-useless-concat:
    - 2

  # Disallow Yoda Conditions
  yoda:
    - 2

  # Disallow Early Use
  no-use-before-define:
    - 2

  # Require file to end with single newline
  eol-last:
    - 2

  # Disallow trailing spaces at the end of lines
  no-trailing-spaces:
    - 2

  # Disallow Dangling Underscores in Identifiers
  no-underscore-dangle:
    - 2

  # Require JSDoc comment
  require-jsdoc:
    - 2

  # Require Or Disallow Space Before Blocks
  space-before-blocks:
    - 2