.eslintrc.json

{
  "env": {
    "browser": true,
    "node": true,
    "es6": true,
    "mocha": true
  },
  "parserOptions": {
    "ecmaVersion": 6,
    "sourceType": "module",
    "ecmaFeatures": {
      "impliedStrict": true,
      "experimentalObjectRestSpread": true
    }
  },
  "globals": {},
  "rules": {
    /* Possible Errors */
    // disallow assignment operators in conditional expressions
    "no-cond-assign": 2,
    // disallow the use of console
    "no-console": 1,
    // disallow constant expressions in conditions
    "no-constant-condition": 2,
    // disallow the use of debugger
    "no-debugger": 2,
    // disallow duplicate arguments in function definitions
    "no-dupe-args": 2,
    // disallow duplicate keys in object literals
    "no-dupe-keys": 2,
    // disallow duplicate case labels
    "no-duplicate-case": 2,
    // disallow empty character classes in regular expressions
    "no-empty-character-class": 2,
    // disallow empty block statements
    "no-empty": [
      1,
      {
        "allowEmptyCatch": true
      }
    ],
    // disallow reassigning exceptions in catch clauses
    "no-ex-assign": 2,
    // disallow unnecessary boolean casts
    "no-extra-boolean-cast": 2,
    // disallow unnecessary parentheses
    "no-extra-parens": 2,
    // disallow unnecessary semicolons
    "no-extra-semi": 2,
    // disallow reassigning function declarations
    "no-func-assign": 2,
    // disallow function or var declarations in nested blocks
    "no-inner-declarations": [
      2,
      "both"
    ],
    // disallow invalid regular expression strings in RegExp constructors
    "no-invalid-regexp": 2,
    // disallow irregular whitespace outside of strings and comments
    "no-irregular-whitespace": [
      2,
      {
        "skipStrings": true,
        "skipComments": true,
        "skipRegExps": true,
        "skipTemplates": true
      }
    ],
    // disallow negating the left operand in in expressions
    "no-negated-in-lhs": 2,
    // disallow calling global object properties as functions
    "no-obj-calls": 2,
    // disallow use of Object.prototypes builtins directly
    "no-prototype-builtins": 2,
    //disallow multiple spaces in regular expression literals
    "no-regex-spaces": 2,
    // disallow sparse arrays
    "no-sparse-arrays": 1,
    // disallow confusing multiline expressions
    "no-unexpected-multiline": 1,
    // disallow unreachable code after return, throw, continue, and break statements
    "no-unreachable": 2,
    // disallow control flow statements in finally blocks
    "no-unsafe-finally": 1,
    // require calls to isNaN() when checking for NaN
    "use-isnan": 2,
    // enforce valid JSDoc comments
    "valid-jsdoc": 1,
    // enforce comparing typeof expressions against valid strings
    "valid-typeof": 2,
    /* Best Practices */
    // Enforces getter/setter pairs in objects
    "accessor-pairs": 1,
    // Enforces return statements in callbacks of array’s methods
    "array-callback-return": 1,
    // enforce the use of variables within the scope they are defined
    "block-scoped-var": 1,
    // enforce consistent brace style for all control statements
    "curly": 1,
    // require default cases in switch statements
    "default-case": 1,
    // enforce consistent newlines before and after dots
    "dot-notation": 1,
    // require the use of === and !==
    "eqeqeq": [
      2,
      "allow-null"
    ],
    // require for-in loops to include an if statement
    "guard-for-in": 1,
    // disallow the use of alert, confirm, and prompt
    "no-alert": 1,
    // disallow the use of arguments.caller or arguments.callee
    "no-caller": 2,
    // disallow the use of eval()
    "no-eval": 2,
    // disallow extending native types
    "no-extend-native": 1,
    // disallow unnecessary calls to .bind()
    "no-extra-bind": 1,
    // disallow leading or trailing decimal points in numeric literals
    "no-floating-decimal": 2,
    // disallow var and named function declarations in the global scope
    "no-implicit-globals": 1,
    // disallow the use of eval()-like methods
    "no-implied-eval": 2,
    // disallow unnecessary nested blocks
    "no-lone-blocks": 1,
    // disallow function declarations and expressions inside loop statements
    "no-loop-func": 1,
    // disallow multiple spaces
    "no-multi-spaces": 1,
    // disallow var redeclaration
    "no-redeclare": [
      2,
      {
        "builtinGlobals": true
      }
    ],
    // disallow comma operators
    "no-sequences": 1,
    // require var declarations be placed at the top of their containing scope
    "vars-on-top": 1,
    // require parentheses around immediate function invocations
    "wrap-iife": 1,
    // require or disallow “Yoda” conditions
    "yoda": 1,
    /* Strict Mode */
    "strict": [
      1,
      "function"
    ],
    /* Variables */
    // disallow deleting variables
    "no-delete-var": 2,
    // disallow specified global variables
    "no-restricted-globals": 2,
    // disallow unused variables
    "no-unused-vars": 1,
    // disallow the use of variables before they are defined
    "no-use-before-define": 2,
    // Disallow Use of undefined Variable
    "no-undef": 2,
    // disallow initializing variables to undefined
    "no-undef-init": 1,
    // disallow the use of undefined as an identifier
    "no-undefined": 1,
    // disallow var declarations from shadowing variables in the outer scope
    "no-shadow": [
      2,
      {
        "hoist": "functions"
      }
    ],
    /* Stylistic Issues */
    // enforce consistent spacing inside array brackets
    "array-bracket-spacing": [
      1,
      "never"
    ],
    // enforce consistent spacing inside single-line blocks
    "block-spacing": [
      1,
      "never"
    ],
    // enforce consistent brace style for blocks
    "brace-style": [
      1,
      "1tbs",
      {
        "allowSingleLine": true
      }
    ],
    // require or disallow trailing commas,
    "comma-dangle": 1,
    // enforce consistent spacing before and after commas
    "comma-spacing": [
      1,
      {
        "before": false,
        "after": true
      }
    ],
    // enforce consistent comma style
    "comma-style": [
      1,
      "last"
    ],
    // enforce consistent spacing inside computed property brackets
    "computed-property-spacing": [
      1,
      "never"
    ],
    // enforce consistent naming when capturing the current execution context
    "consistent-this": [
      1,
      "that"
    ],
    // enforce at least one newline at the end of files
    "eol-last": 1,
    // disallow specified identifiers
    "id-blacklist": 1,
    // enforce consistent indentation
    "indent": [
      1,
      2,
      {
        "SwitchCase": 1
      }
    ],
    // enforce consistent spacing between keys and values in object literal properties
    "key-spacing": [
      1,
      {
        "afterColon": true
      }
    ],
    // enforce consistent spacing before and after keywords
    "keyword-spacing": 1,
    // enforce a maximum line length
    "max-len": [
      1,
      100,
      2,
      {
        "ignoreComments": true,
        "ignoreTrailingComments": true,
        "ignoreUrls": true,
        "ignoreStrings": true,
        "ignoreTemplateLiterals": true,
        "ignoreRegExpLiterals": true
      }
    ],
    // enforce a maximum number of parameters in function definitions
    "max-params": [
      1,
      3
    ],
    // require constructor function names to begin with a capital letter
    "new-cap": 1,
    // require parentheses when invoking a constructor with no arguments
    "new-parens": 1,
    // disallow mixed spaces and tabs for indentation
    "no-mixed-spaces-and-tabs": 1,
    // disallow multiple empty lines
    "no-multiple-empty-lines": [
      1,
      {
        "max": 1,
        "maxBOF": 0,
        "maxEOF": 1
      }
    ],
    // disallow spacing between function identifiers and their applications
    "no-spaced-func": 1,
    // disallow trailing whitespace at the end of lines
    "no-trailing-spaces": 1,
    // disallow ternary operators when simpler alternatives exist
    "no-unneeded-ternary": 1,
    // disallow whitespace before properties
    "no-whitespace-before-property": 1,
    // enforce consistent spacing inside braces
    "object-curly-spacing": [
      0
    ],
    // enforce the consistent use of either backticks, double, or single quotes
    "quotes": [
      1,
      "single",
      {
        "avoidEscape": true,
        "allowTemplateLiterals": true
      }
    ],
    // enforce consistent spacing before and after semicolons
    "semi-spacing": [
      1,
      {
        "before": false,
        "after": true
      }
    ],
    // require or disallow semicolons instead of ASI
    "semi": 1,
    // enforce consistent spacing before blocks
    "space-before-blocks": 1,
    // enforce consistent spacing before function definition opening parenthesis
    "space-before-function-paren": [
      1,
      {
        "anonymous": "always",
        "named": "never"
      }
    ],
    // enforce consistent spacing inside parentheses
    "space-in-parens": [
      1,
      "never"
    ],
    // require spacing around operators
    "space-infix-ops": 1,
    // enforce consistent spacing after the // or /* in a comment
    "spaced-comment": [
      1,
      "always"
    ],
    /* ECMAScript 6 */
    // require braces around arrow function bodies
    "arrow-body-style": [
      1,
      "as-needed"
    ],
    // require parentheses around arrow function arguments
    "arrow-parens": [
      1,
      "as-needed"
    ],
    // enforce consistent spacing before and after the arrow in arrow functions
    "arrow-spacing": [
      1,
      {
        "before": true,
        "after": true
      }
    ],
    // require super() calls in constructors
    "constructor-super": 2,
    // enforce consistent spacing around * operators in generator functions
    "generator-star-spacing": [
      1,
      {
        "before": true,
        "after": false
      }
    ],
    // disallow reassigning class members
    "no-class-assign": 2,
    // disallow arrow functions where they could be confused with comparisons
    "no-confusing-arrow": 0,
    // disallow reassigning const variables
    "no-const-assign": 2,
    // disallow duplicate class members
    "no-dupe-class-members": 1,
    // disallow duplicate module imports
    "no-duplicate-imports": [
      1,
      {
        "includeExports": true
      }
    ],
    // disallow new operators with the Symbol object
    "no-new-symbol": 2,
    // disallow specified modules when loaded by import
    "no-restricted-imports": [
      2,
      "assert",
      "buffer",
      "child_process",
      "cluster",
      "crypto",
      "dgram",
      "dns",
      "domain",
      "events",
      "freelist",
      "fs",
      "http",
      "https",
      "module",
      "net",
      "os",
      "path",
      "punycode",
      "querystring",
      "readline",
      "repl",
      "smalloc",
      "stream",
      "string_decoder",
      "sys",
      "timers",
      "tls",
      "tracing",
      "tty",
      "url",
      "util",
      "vm",
      "zlib"
    ],
    // disallow this/super before calling super() in constructors
    "no-this-before-super": 2,
    // disallow unnecessary computed property keys in object literals
    "no-useless-computed-key": 1,
    // disallow unnecessary constructors
    "no-useless-constructor": 1,
    // disallow renaming import, export, and destructured assignments to the same name
    "no-useless-rename": 1,
    // require let or const instead of var
    "no-var": 1,
    // require rest parameters instead of arguments
    "prefer-rest-params": 1,
    // require template literals instead of string concatenation
    "prefer-template": 1,
    // require generator functions to contain yield
    "require-yield": 2,
    // enforce spacing between rest and spread operators and their expressions
    "rest-spread-spacing": [
      1,
      "never"
    ],
    // require or disallow spacing around embedded expressions of template strings
    "template-curly-spacing": [
      1,
      "never"
    ],
    // require or disallow spacing around the * in yield* expressions
    "yield-star-spacing": [
      1,
      {
        "before": true,
        "after": false
      }
    ]
  }
}