.eslintrc.json

{
  "env": {
    "node": true,
    "es6": true
  },

  "parserOptions": {
    "sourceType": "module"
  },

  "rules": {
    // Possible Errors
    // The following rules point out areas where you might have made mistakes.

    "comma-dangle": [2, "never"],               // - disallow or enforce trailing commas (recommended)
    "no-cond-assign": 2,                        // - disallow assignment in conditional expressions (recommended)
    "no-console": 2,                            // - disallow use of console in the node environment (recommended)
    "no-constant-condition": 2,                 // - disallow use of constant expressions in conditions (recommended)
    "no-control-regex": 2,                      // - disallow control characters in regular expressions (recommended)
    "no-debugger": 2,                           // - disallow use of debugger (recommended)
    "no-dupe-args": 2,                          // - disallow duplicate arguments in functions (recommended)
    "no-dupe-keys": 2,                          // - disallow duplicate keys when creating object literals (recommended)
    "no-duplicate-case": 2,                     // - disallow a duplicate case label. (recommended)
    "no-empty-character-class": 2,              // - disallow the use of empty character classes in regular expressions (recommended)
    "no-empty": 0,                              // - disallow empty statements (recommended)
    "no-ex-assign": 2,                          // - disallow assigning to the exception in a catch block (recommended)
    "no-extra-boolean-cast": 2,                 // - disallow double-negation boolean casts in a boolean context (recommended)
    "no-extra-parens": 0,                       // - disallow unnecessary parentheses
    "no-extra-semi": 2,                         // - disallow unnecessary semicolons (recommended)
    "no-func-assign": 2,                        // - disallow overwriting functions written as function declarations (recommended)
    "no-inner-declarations": [2, "functions"],  // - disallow function or variable declarations in nested blocks (recommended)
    "no-invalid-regexp": 2,                     // - disallow invalid regular expression strings in the RegExp constructor (recommended)
    "no-irregular-whitespace": 2,               // - disallow irregular whitespace outside of strings and comments (recommended)
    "no-negated-in-lhs": 2,                     // - disallow negation of the left operand of an in expression (recommended)
    "no-obj-calls": 2,                          // - disallow the use of object properties of the global object (Math and JSON) as functions (recommended)
    "no-regex-spaces": 2,                       // - disallow multiple spaces in a regular expression literal (recommended)
    "no-sparse-arrays": 0,                      // - disallow sparse arrays (recommended) Note: set to false because array destructuring in ES6
    "no-unreachable": 2,                        // - disallow unreachable statements after a return, throw, continue, or break statement (recommended)
    "use-isnan": 2,                             // - disallow comparisons with the value NaN (recommended)
    "valid-jsdoc": 2,                           // - Ensure JSDoc comments are valid
    "valid-typeof": 2,                          // - Ensure that the results of typeof are compared against a valid string (recommended)
    "no-unexpected-multiline": 2,               // - Avoid code that looks like two expressions but is actually one

    // Best Practices
    // These are rules designed to prevent you from making mistakes. They either prescribe a better way of doing something or help you avoid footguns.

    "accessor-pairs": 2,                        // - Enforces getter/setter pairs in objects
    "block-scoped-var": 0,                      // - treat var statements as if they were block scoped
    "complexity": [1, 9],                       // - specify the maximum cyclomatic complexity allowed in a program
    "consistent-return": 0,                     // - require return statements to either always or never specify values
    "curly": [0,  "all"],                       // - specify curly brace conventions for all control statements
    "default-case": 0,                          // - require default case in switch statements
    "dot-notation": 2,                          // - encourages use of dot notation whenever possible
    "dot-location": [2, "property"],            // - enforces consistent newlines before or after dots
    "eqeqeq": 2,                                // - require the use of === and !==
    "guard-for-in": 2,                          // - make sure for-in loops have an if statement
    "no-alert": 2,                              // - disallow the use of alert, confirm, and prompt
    "no-caller": 2,                             // - disallow use of arguments.caller or arguments.callee
    "no-div-regex": 2,                          // - disallow division operators explicitly at beginning of regular expression
    "no-else-return": 2,                        // - disallow else after a return in an if
    "no-eq-null": 2,                            // - disallow comparisons to null without a type-checking operator
    "no-eval": 2,                               // - disallow use of eval()
    "no-extend-native": 2,                      // - disallow adding to native types
    "no-extra-bind": 2,                         // - disallow unnecessary function binding
    "no-fallthrough": 2,                        // - disallow fallthrough of case statements (recommended)
    "no-floating-decimal": 2,                   // - disallow the use of leading or trailing decimal points in numeric literals
    "no-implicit-coercion": 2,                  // - disallow the type conversions with shorter notations
    "no-implied-eval": 2,                       // - disallow use of eval()-like methods
    "no-invalid-this": 2,                       // - disallow this keywords outside of classes or class-like objects
    "no-iterator": 2,                           // - disallow usage of __iterator__ property
    "no-labels": 2,                             // - disallow use of labeled statements
    "no-lone-blocks": 2,                        // - disallow unnecessary nested blocks
    "no-loop-func": 2,                          // - disallow creation of functions within loops
    "no-multi-spaces": 2,                       // - disallow use of multiple spaces
    "no-multi-str": 2,                          // - disallow use of multiline strings
    "no-native-reassign": 2,                    // - disallow reassignments of native objects
    "no-new-func": 2,                           // - disallow use of new operator for Function object
    "no-new-wrappers": 2,                       // - disallows creating new instances of String,Number, and Boolean
    "no-new": 2,                                // - disallow use of the new operator when not part of an assignment or comparison
    "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 (recommended)
    "no-param-reassign": 0,                     // - disallow reassignment of function parameters
    "no-process-env": 2,                        // - disallow use of process.env
    "no-proto": 2,                              // - disallow usage of __proto__ property
    "no-redeclare": 2,                          // - disallow declaring the same variable more than once (recommended)
    "no-return-assign": 2,                      // - disallow use of assignment in return statement
    "no-script-url": 2,                         // - disallow use of javascript: urls.
    "no-self-compare": 2,                       // - disallow comparisons where both sides are exactly the same
    "no-sequences": 2,                          // - disallow use of the comma operator
    "no-throw-literal": 2,                      // - restrict what can be thrown as an exception
    "no-unused-expressions": 0,                 // - disallow usage of expressions in statement position
    "no-useless-call": 2,                       // - disallow unnecessary .call() and .apply()
    "no-void": 2,                               // - disallow use of the void operator
    "no-warning-comments": 0,                   // - disallow usage of configurable warning terms in comments - e.g. TODO or FIXME
    "no-with": 2,                               // - disallow use of the with statement
    "radix": 2,                                 // - require use of the second argument for parseInt()
    "vars-on-top": 2,                           // - require declaration of all vars at the top of their containing scope
    "wrap-iife": 2,                             // - require immediate function invocation to be wrapped in parentheses
    "yoda": 2,                                  // - require or disallow Yoda conditions

    // Strict Mode
    // These rules relate to using strict mode.

    "strict": ["error", "global"],                    // - controls location of Use Strict Directives

    // Variables
    // These rules have to do with variable declarations.

    "init-declarations": 0,                     // - enforce or disallow variable initializations at definition
    "no-catch-shadow": 2,                       // - disallow the catch clause parameter name being the same as a variable in the outer scope
    "no-delete-var": 2,                         // - disallow deletion of variables (recommended)
    "no-label-var": 2,                          // - disallow labels that share a name with a variable
    "no-shadow-restricted-names": 2,            // - disallow shadowing of names such as arguments
    "no-shadow": 2,                             // - disallow declaration of variables already declared in the outer scope
    "no-undef-init": 2,                         // - disallow use of undefined when initializing variables
    "no-undef": 2,                              // - disallow use of undeclared variables unless mentioned in a /*global */ block (recommended)
    "no-undefined": 0,                          // - disallow use of undefined variable
    "no-unused-vars": 2,                        // - disallow declaration of variables that are not used in the code (recommended)
    "no-use-before-define": 2,                  // - disallow use of variables before they are defined

    // Node.js
    // These rules are specific to JavaScript running on Node.js.

    "callback-return": 2,                       // - enforce return after a callback
    "handle-callback-err": 2,                   // - enforce error handling in callbacks
    "no-mixed-requires": 2,                     // - disallow mixing regular variable and require declarations
    "no-new-require": 2,                        // - disallow use of new operator with the require function
    "no-path-concat": 2,                        // - disallow string concatenation with __dirname and __filename
    "no-process-exit": 2,                       // - disallow process.exit()
    "no-restricted-modules": 2,                 // - restrict usage of specified node modules
    "no-sync": 2,                               // - disallow use of synchronous methods

    // Stylistic Issues
    // These rules are purely matters of style and are quite subjective.

    "array-bracket-spacing": 2,                 // - enforce spacing inside array brackets
    "brace-style": 0,                           // - enforce one true brace style
    "camelcase": 2,                             // - require camel case names
    "comma-spacing": 2,                         // - enforce spacing before and after comma
    "comma-style": 2,                           // - enforce one true comma style
    "computed-property-spacing": 2,             // - require or disallow padding inside computed properties
    "consistent-this": 0,                       // - enforce consistent naming when capturing the current execution context
    "eol-last": 2,                              // - enforce newline at the end of file, with no multiple empty lines
    "func-names": 0,                            // - require function expressions to have a name
    "func-style": [0, "declaration"],           // - enforce use of function declarations or expressions
    "id-length": [1,
      {
        "min": 2,
        "max": 45,
        "exceptions": ["a", "i", "j", "k", "n", "Q"]
      }
    ],                                          // - this option enforces minimum and maximum identifier lengths (variable names, property names etc.) (off by default)
    "id-match": 0,                              // - require identifiers to match the provided regular expression
    "indent": [2, 2],                           // - specify tab or space width for your code
    "key-spacing": 2,                           // - enforce spacing between keys and values in object literal properties
    "lines-around-comment": [0,
      {
        "beforeBlockComment": true,
        "afterBlockComment": false,
        "beforeLineComment": false,
        "afterLineComment": false,
        "allowBlockStart": true,
        "allowBlockEnd": true
      }
    ],                                          // - enforce empty lines around comments
    "linebreak-style": 2,                       // - disallow mixed 'LF' and 'CRLF' as linebreaks
    "max-nested-callbacks": [2, 6],             // - specify the maximum depth callbacks can be nested
    "new-cap": 0,                               // - require a capital letter for constructors
    "new-parens": 2,                            // - disallow the omission of parentheses when invoking a constructor with no arguments
    "newline-after-var": 0,                     // - require or disallow an empty newline after variable declarations
    "no-array-constructor": 2,                  // - disallow use of the Array constructor
    "no-continue": 0,                           // - disallow use of the continue statement
    "no-inline-comments": 0,                    // - disallow comments inline after code
    "no-lonely-if": 2,                          // - disallow if as the only statement in an else block
    "no-mixed-spaces-and-tabs": 2,              // - disallow mixed spaces and tabs for indentation (recommended)
    "no-multiple-empty-lines": 2,               // - disallow multiple empty lines
    "no-nested-ternary": 2,                     // - disallow nested ternary expressions
    "no-new-object": 2,                         // - disallow the use of the Object constructor
    "no-spaced-func": 2,                        // - disallow space between function identifier and application
    "no-ternary": 0,                            // - disallow the use of ternary operators
    "no-trailing-spaces": 2,                    // - disallow trailing whitespace at the end of lines
    "no-underscore-dangle": 0,                  // - disallow dangling underscores in identifiers
    "no-unneeded-ternary": 2,                   // - disallow the use of Boolean literals in conditional expressions
    "object-curly-spacing": 0,                  // - require or disallow padding inside curly braces
    "one-var": ["error", "never"],              // - require or disallow one variable declaration per function
    "operator-assignment": [2, "always"],       // - require assignment operator shorthand where possible or prohibit it entirely
    "operator-linebreak": 2,                    // - enforce operators to be placed before or after line breaks
    "padded-blocks": 0,                         // - enforce padding within blocks
    "quote-props": 0,                           // - require quotes around object literal property names
    "quotes": [2, "double"],                    // - specify whether backticks, double or single quotes should be used
    "semi-spacing": 2,                          // - enforce spacing before and after semicolons
    "semi": 2,                                  // - require or disallow use of semicolons instead of ASI
    "sort-vars": 0,                             // - sort variables within the same declaration block
    "space-before-blocks": 2,                   // - require or disallow a space before blocks
    "space-before-function-paren": [2,
      {
        "anonymous": "always",
        "named": "never"
      }
    ],                                          //  - require or disallow a space before function opening parenthesis
    "space-in-parens": 2,                       //  - require or disallow spaces inside parentheses
    "space-infix-ops": 2,                       // - require spaces around operators
    "space-unary-ops": 2,                       // - require or disallow spaces before/after unary operators
    "spaced-comment": 2,                        // - require or disallow a space immediately following the // or /* in a comment
    "wrap-regex": 2,                            // - require regex literals to be wrapped in parentheses

    // ECMAScript 6
    // These rules are only relevant to ES6 environments.

    "arrow-parens": [2, "as-needed"],           // - require parens in arrow function arguments
    "arrow-spacing": 2,                         // - require space before/after arrow function's arrow
    "constructor-super": 2,                     // - verify calls of super() in constructors
    "generator-star-spacing": 2,                // - enforce spacing around the * in generator functions
    "no-class-assign": 2,                       // - disallow modifying variables of class declarations
    "no-const-assign": 2,                       // - disallow modifying variables that are declared using const
    "no-this-before-super": 2,                  // - disallow use of this/super before calling super() in constructors.
    "no-var": 2,                                // - require let or const instead of var
    "object-shorthand": [2, "methods"],         // - require method and property shorthand syntax for object literals
    "prefer-const": 1,                          // - suggest using const declaration for variables that are never modified after declared
    "prefer-spread": 2,                         // - suggest using the spread operator instead of .apply().
    "prefer-reflect": 0,                        // - suggest using Reflect methods where applicable
    "require-yield": 2,                         // - disallow generator functions that do not have yield
    "prefer-template": 2,

    "keyword-spacing": [2, {
      "before": true,
      "after": true
    }]

  }
}