.eslintrc

parserOptions:
    ecmaVersion: 6

env:
    node: true               # Node.js global variables and Node.js-specific rules
    es6: true                # Required for things like Promise constructors to be recognized

rules:

    # Possible Errors

    comma-dangle: ["error", "never"]           # disallow trailing commas
    no-cond-assign:  ["error", "always"]       # disallow assignment operators in conditional expressions
    no-console: "warn"                         # disallow the use of console
    no-constant-condition: "error"             # disallow constant expressions in conditions
    no-control-regex: "error"                  # disallow control characters in regular expressions
    no-debugger: "error"                       # disallow the use of debugger
    no-dupe-args: "error"                      # disallow duplicate arguments in function definitions
    no-dupe-keys: "error"                      # disallow duplicate keys in object literals
    no-duplicate-case: "error"                 # disallow duplicate case labels
    no-empty: "error"                          # disallow empty block statements
    no-empty-character-class: "error"          # disallow empty character classes in regular expressions
    no-ex-assign: "error"                      # disallow reassigning exceptions in catch clauses
    no-extra-boolean-cast: "error"             # disallow unnecessary boolean casts
    no-extra-parens: 0                         # disallow unnecessary parentheses
    no-extra-semi: "error"                     # disallow unnecessary semicolons
    no-func-assign: "error"                    # disallow reassigning function declarations
    no-inner-declarations: "error"             # disallow function or var declarations in nested blocks
    no-invalid-regexp: "error"                 # disallow invalid regular expression strings in RegExp constructors
    no-irregular-whitespace: "error"           # disallow irregular whitespace outside of strings and comments
    no-negated-in-lhs: "error"                 # disallow negating the left operand in in expressions
    no-obj-calls: "error"                      # disallow calling global object properties as functions
    no-regex-spaces: "error"                   # disallow multiple spaces in regular expression literals
    no-sparse-arrays: "error"                  # disallow sparse arrays
    no-unexpected-multiline: "error"           # disallow confusing multiline expressions
    no-unreachable: "error"                    # disallow unreachable code after return, throw, continue, and break statements
    no-unsafe-finally: "error"                 # disallow control flow statements in finally blocks
    use-isnan: "error"                         # require calls to isNaN() when checking for NaN
    valid-jsdoc: 0                             # enforce valid JSDoc comments
    valid-typeof: "error"                      # enforce comparing typeof expressions against valid strings


    # Best Practice

    accessor-pairs: "error"                    # enforces getter/setter pairs in objects (off by default)
    block-scoped-var: "error"                  # 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
    curly: ["error", "all"]                    # specify curly brace conventions for all control statements
    default-case: "error"                      # require default case in switch statements (off by default)
    dot-notation: "error"                      # encourages use of dot notation whenever possible
    dot-location: ["error", "property"]        # enforces consistent newlines before or after dots (off by default)
    eqeqeq: "error"                            # require the use of === and !==
    guard-for-in: "error"                      # make sure for-in loops have an if statement (off by default)
    no-alert: "error"                          # disallow the use of alert, confirm, and prompt
    no-caller: "error"                         # disallow use of arguments.caller or arguments.callee
    no-confusing-arrow: "error"                # disallow arrow functions where they could be confused with comparisons
    no-div-regex: "error"                      # disallow division operators explicitly at beginning of regular expression (off by default)
    no-else-return: "error"                    # disallow else after a return in an if (off by default)
    no-eq-null: "error"                        # disallow comparisons to null without a type-checking operator (off by default)
    no-eval: "error"                           # disallow use of eval()
    no-extend-native: "error"                  # disallow adding to native types
    no-extra-bind: "error"                     # disallow unnecessary function binding
    no-fallthrough: "error"                    # disallow fallthrough of case statements
    no-floating-decimal: "error"               # disallow the use of leading or trailing decimal points in numeric literals (off by default)
    no-implied-eval: "error"                   # disallow use of eval()-like methods
    no-iterator: "error"                       # disallow usage of __iterator__ property
    no-labels: "error"                         # disallow use of labeled statements
    no-lone-blocks: "error"                    # disallow unnecessary nested blocks
    no-loop-func: "error"                      # disallow creation of functions within loops
    no-multi-spaces: "error"                   # disallow use of multiple spaces
    no-multi-str: "error"                      # disallow use of multiline strings
    no-native-reassign: "error"                # disallow reassignments of native objects
    no-new-func: "error"                       # disallow use of new operator for Function object
    no-new-wrappers: "error"                   # disallows creating new instances of String, Number, and Boolean
    no-new: "error"                            # disallow use of new operator when not part of the assignment or comparison
    no-octal-escape: "error"                   # disallow use of octal escape sequences in string literals, such as var foo = "Copyright \251";
    no-octal: "error"                          # disallow use of octal literals
    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: "error"                          # disallow usage of __proto__ property
    no-redeclare: "error"                      # disallow declaring the same variable more then once
    no-return-assign: "error"                  # disallow use of assignment in return statement
    no-script-url: "error"                     # disallow use of javascript: urls
    no-self-compare: "error"                   # disallow comparisons where both sides are exactly the same (off by default)
    no-sequences: "error"                      # disallow use of comma operator
    no-throw-literal: "error"                  # restrict what can be thrown as an exception (off by default)
    no-unused-expressions: "error"             # disallow usage of expressions in statement position
    no-void: "error"                           # disallow use of void operator (off by default)
    no-warning-comments: "warn"                # disallow usage of configurable erroring terms in comments, e.g. TODO or FIXME (off by default)
    no-with: "error"                           # disallow use of the with statement
    radix: "error"                             # require use of the second argument for parseInt() (off by default)
    vars-on-top: "error"                       # requires to declare all vars on top of their containing scope (off by default)
    wrap-iife: "error"                         # require immediate function invocation to be wrapped in parentheses (off by default)
    yoda: 0                                    # require or disallow Yoda conditions


    # Strict Mode

    strict: "error"          # controls location of Use Strict Directives


    # Variables

    no-catch-shadow: "error"                   # 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: "error"                      # disallow labels that share a name with a variable
    no-shadow: "error"                         # disallow declaration of variables already declared in the outer scope
    no-shadow-restricted-names: "error"        # disallow shadowing of names such as arguments
    no-undef: "error"                          # disallow use of undeclared variables unless mentioned in a /*global */ block
    no-undef-init: "error"                     # disallow use of undefined when initializing variables
    no-undefined: 0                            # disallow use of undefined variable (off by default)
    no-unused-vars: "error"                    # disallow declaration of variables that are not used in the code
    no-use-before-define: ["error", "nofunc"]  # disallow use of variables before they are defined


    # Node.js

    handle-callback-err: "warn"        # enforces error handling in callbacks (off by default) (on by default in the node environment)
    no-mixed-requires: "error"         # disallow mixing regular variable and require declarations (off by default) (on by default in the node environment)
    no-new-require: "error"            # disallow use of new operator with the require function (off by default) (on by default in the node environment)
    no-path-concat: "error"            # disallow string concatenation with __dirname and __filename (off by default) (on by default in the node environment)
    no-process-exit: 0                 # disallow process.exit() (on by default in the node environment)
    no-restricted-modules: 0           # restrict usage of specified node modules (off by default)
    no-sync: "warn"                    # disallow use of synchronous methods (off by default)


    # Stylistic Issues

    array-bracket-spacing: ["error", "never"]                                  # enforce spacing inside array brackets (off by default)
    brace-style: ["error", "1tbs"]                                             # enforce one true brace style (off by default)
    camelcase: "error"                                                         # require camel case names
    comma-spacing: ["error", {before: false, after: true}]                     # enforce spacing before and after comma
    comma-style: ["error", "last"]                                             # enforce one true comma style (off by default)
    computed-property-spacing: ["error", "never"]                              # require or disallow padding inside computed properties (off by default)
    consistent-this: ["error", "that"]                                         # enforces consistent naming when capturing the current execution context (off by default)
    eol-last: "error"                                                          # enforce newline at the end of file, with no multiple empty lines
    func-names: 0                                                              # require function expressions to have a name (off by default)
    func-style: 0                                                              # enforces use of function declarations or expressions (off by default)
    indent: ["error", 4]                                                       # this option sets a specific tab width for your code (off by default)
    key-spacing: ["error", {beforeColon: false, afterColon: true}]             # enforces spacing between keys and values in object literal properties
    lines-around-comment: 0                                                    # enforces empty lines around comments (off by default)
    linebreak-style: ["error", "unix"]                                         # disallow mixed 'LF' and 'CRLF' as linebreaks (off by default)
    max-nested-callbacks: ["error", 5]                                         # require a capital letter for constructors
    new-parens: "error"                                                        # allow/disallow an empty newline after var statement (off by default)
    no-array-constructor: "error"                                              # disallow use of the Array constructor
    no-continue: "error"                                                       # disallow use of the continue statement (off by default)
    no-inline-comments: 0                                                      # disallow comments inline after code (off by default)
    no-lonely-if: "error"                                                      # disallow if as the only statement in an else block (off by default)
    no-mixed-spaces-and-tabs: "error"                                          # disallow mixed spaces and tabs for indentation
    no-multiple-empty-lines: 0                                                 # disallow multiple empty lines (off by default)
    no-nested-ternary: "error"                                                 # disallow nested ternary expressions (off by default)
    no-new-object: 0                                                           # disallow use of the Object constructor
    no-spaced-func: "error"                                                    # disallow space between function identifier and application
    no-ternary: 0                                                              # disallow the use of ternary operators (off by default)
    no-trailing-spaces: "error"                                                # disallow trailing whitespace at the end of lines
    no-underscore-dangle: "error"                                              # disallow dangling underscores in identifiers
    one-var: 0                                                                 # allow just one var statement per function (off by default)
    operator-assignment: ["error", "always"]                                   # require assignment operator shorthand where possible or prohibit it entirely (off by default)
    operator-linebreak: ["error", "before"]                                    # enforce operators to be placed before or after line breaks (off by default)
    padded-blocks: 0                                                           # enforce padding within blocks (off by default)
    quote-props: 0                                                             # require quotes around object literal property names (off by default)
    quotes: ["error", "double", {allowTemplateLiterals: true}]                 # specify whether double or single quotes should be used
    semi-spacing: ["error", {before: false, after: true}]                      # enforce spacing before and after semicolons
    semi: ["error", "always"]                                                  # require or disallow use of semicolons instead of ASI
    sort-vars: 0                                                               # sort variables within the same declaration block (off by default)
    keyword-spacing: ["error", {before: true, after: true}]                    # require a space before or after certain keywords
    space-before-blocks: ["error", "always"]                                   # require or disallow space before blocks (off by default)
    space-before-function-paren: ["error", {anonymous: always, named: never}]  # require or disallow space before function opening parenthesis (off by default)
    space-in-parens: ["error", "never"]                                        # require or disallow spaces inside parentheses (off by default)
    space-infix-ops: "error"                                                   # require spaces around operators
    space-unary-ops: "error"                                                   # require or disallow spaces before/after unary operators (words on by default, nonwords off by default)
    spaced-comment: ["error", "always"]                                        # require or disallow a space immediately following the # or /* in a comment (off by default)
    wrap-regex: "error"                                                        # require regex literals to be wrapped in parentheses (off by default)


    # ECMAScript 6

    constructor-super: "error"         # verify super() callings in constructors (off by default)
    generator-star-spacing: 0          # enforce the spacing around the * in generator functions (off by default)
    no-this-before-super: "error"      # disallow to use this/super before super() calling in constructors (off by default)
    no-var: "error"                    # require let or const instead of var (off by default)
    object-shorthand: 0                # require method and property shorthand syntax for object literals (off by default)
    prefer-const: "error"              # suggest using of const declaration for variables that are never modified after declared (off by default)


    # Legacy

    max-depth: ["error", 5]            # specify the maximum depth that blocks can be nested (off by default)
    max-len: ["error", 120]            # specify the maximum length of a line in your program (off by default)
    max-params: ["error", 4]           # limits the number of parameters that can be used in the function declaration. (off by default)
    max-statements: 0                  # specify the maximum number of statement allowed in a function (off by default)
    no-bitwise: "error"                # disallow use of bitwise operators (off by default)
    no-plusplus: "error"               # disallow use of unary operators, ++ and -- (off by default)