.eslintrc

{
  "globals" : {
    "module": true,
    "Reflect": true // for Reflect.deleteProperty()
  },
  "env": {
    "browser": true,
    "node": true,
    "es6" : true
  },
  "parser": "babel-eslint",
    "parserOptions": {
        "ecmaFeatures": {
            "arrowFunctions": true, //enable arrow functions
            "binaryLiterals": true, //enable binary literals
            "blockBindings": true, //enable let and const (aka block bindings)
            "classes": true, //enable classes
            "defaultParams": true, //enable default function parameters
            "destructuring": true, //enable destructuring
            "forOf": true, //enable for-of loops
            "generators": true, //enable generators
            "modules": true, //enable modules and global strict mode
            "objectLiteralComputedProperties": true, //enable computed object literal property names
            "objectLiteralDuplicateProperties": true, //enable duplicate object literal properties in strict mode
            "objectLiteralShorthandMethods": true, //enable object literal shorthand methods
            "objectLiteralShorthandProperties": true, //enable object literal shorthand properties
            "octalLiterals": true, //enable octal literals
            "regexUFlag": true, //enable the regular expression u flag
            "regexYFlag": true, //enable the regular expression y flag
            "restParams": true, //enable the rest parameters
            "spread": true, //enable the spread operator for arrays
            "superInFunctions": true, //enable super references inside of functions
            "templateStrings": true, //enable template strings
            "unicodeCodePointEscapes": true, //enable code point escapes
            "globalReturn": true, //allow return statements in the global scope
            "jsx": true, //enable JSX
            "experimentalObjectRestSpread": true //enable support for the experimental object rest/spread properties (IMPORTANT: This is an experimental feature that may change significantly in the future. It's recommended that you do not write rules relying on this functionality unless you are willing to incur maintenance cost when it changes.)
        }
    },
    "plugins": [
    "babel",
    "react"
  ],
  "rules": {
    /* Possible Errors */
    "comma-dangle": [2, "never"], //d isallow or enforce trailing commas (recommended)
    "no-cond-assign": [2, "always"], // disallow assignment in conditional expressions (recommended)
    "no-console": 1, // 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": 2, // disallow empty statements (recommended)
    "no-ex-assign": 2, // disallow assigning to the exception in a catch block (recommended)
    "no-extra-boolean-cast": 0, // disallow double-negation boolean casts in a boolean context (not recommended)
    "no-extra-parens": 0, // disallow unnecessary parentheses
    "no-extra-semi": 2, // disallow unnecessary semicolons (recommended) (fixable)
    "no-func-assign": 2, // disallow overwriting functions written as function declarations (recommended)
    "no-inner-declarations":  [2, "both"], // 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": 2, // disallow sparse arrays (recommended)
    "no-unexpected-multiline": 2, // Avoid code that looks like two expressions but is actually one
    "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": 1, // Ensure JSDoc comments are valid
    "valid-typeof": 2, // Ensure that the results of typeof are compared against a valid string (recommended)

    /* Best Practices */
    "block-scoped-var": 0, // treat var statements as if they were block scoped (off by default). 0: deep destructuring is not compatible https://github.com/eslint/eslint/issues/1863
    "complexity": [1, 20], // specify the maximum cyclomatic complexity allowed in a program (off by default)
    "consistent-return": [2, { "treatUndefinedAsUnspecified": false }], // require return statements to either always or never specify values
    "curly": 2, // specify curly brace conventions for all control statements
    "default-case": 2, // require default case in switch statements (off by default)
    "dot-notation": 2, // encourages use of dot notation whenever possible
    "eqeqeq": 2, // require the use of === and !==
    "guard-for-in": 2, // make sure for-in loops have an if statement (off by default)
    "no-alert": 1, // 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 (off by default)
    "no-else-return": 2, // disallow else after a return in an if (off by default)
    "no-eq-null": 2, // disallow comparisons to null without a type-checking operator (off by default)
    "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
    "no-floating-decimal": 2, // disallow the use of leading or trailing decimal points in numeric literals (off by default)
    "no-implied-eval": 2, // disallow use of eval()-like methods
    "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": 2, // disallow use of new operator when not part of the assignment or comparison
    "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-octal": 2, // disallow use of octal literals
    "no-octal-escape": 2, // disallow use of octal escape sequences in string literals, such as var foo = "Copyright \251";
    "no-param-reassign": 2, // disallow reassignment of function parameters (off by default)
    "no-process-env": 0, // disallow use of process.env (off by default)
    "no-proto": 2, // disallow usage of __proto__ property
    "no-redeclare": 2, // disallow declaring the same variable more then once
    "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 (off by default)
    "no-sequences": 2, // disallow use of comma operator
    "no-throw-literal": 2, // restrict what can be thrown as an exception (off by default)
    "no-unused-expressions": 2, // disallow usage of expressions in statement position
    "no-void": 0, // disallow use of void operator (off by default)
    "no-warning-comments": [0, {"terms": ["todo", "fixme"], "location": "start"}], // disallow usage of configurable warning terms in comments": 2, // e.g. TODO or FIXME (off by default)
    "no-with": 2, // disallow use of the with statement
    "radix": 2, // require use of the second argument for parseInt() (off by default)
    "vars-on-top": 2, // requires to declare all vars on top of their containing scope (off by default)
    "wrap-iife": 2, // require immediate function invocation to be wrapped in parentheses (off by default)
    "yoda": 2, // require or disallow Yoda conditions

    /* Strict Mode */
    "strict": [2, "global"],

    /* Variables */
    "init-declarations": [0, "always"], //enforce or disallow variable initializations at definition
    "no-catch-shadow": 1, //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": 2, //disallow use of undefined variable
    "no-unused-vars": [2, { "vars": "local", "args": "after-used" }], //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 and CommonJS */
    "callback-return": 1, //enforce return after a callback
    "global-require": 2, //enforce require() on top-level module scope
    "handle-callback-err": 1, //enforce error handling in callbacks
    "no-mixed-requires": 1, //disallow mixing regular variable and require declarations
    "no-new-require": 1, //disallow use of new operator with the require function
    "no-path-concat": 1, //disallow string concatenation with __dirname and __filename
    "no-process-exit": 1, //disallow process.exit()
    "no-restricted-modules": [1, ""], //restrict usage of specified node modules
    "no-sync": 0, //disallow use of synchronous methods

    /* Stylistic Issues */
    "array-bracket-spacing":[1, "never"], //enforce spacing inside array brackets (fixable)
    "block-spacing": [2, "always"], //disallow or enforce spaces inside of single line blocks (fixable)
    "brace-style": [1, "1tbs", { "allowSingleLine": true }], //enforce one true brace style
    "camelcase": [2, { "properties": "always" }], //require camel case names
    "comma-spacing":  [2, { "before": false, "after": true }], //enforce spacing before and after comma (fixable)
    "comma-style": [2, "last"], //enforce one true comma style
    "computed-property-spacing": 1, //require or disallow padding inside computed properties (fixable)
    "consistent-this": 0, //enforce consistent naming when capturing the current execution context
    "eol-last": 0, //enforce newline at the end of file, with no multiple empty lines (fixable)
    "func-names": 0, //require function expressions to have a name
    "func-style": [2, "declaration"], //enforce use of function declarations or expressions
    "id-length": 0, //this option enforces minimum and space-after-keywordsimum identifier lengths (variable names, property names etc.)
    "id-match": 1, //require identifiers to match the provided regular expression
    "indent": [2,4,{"SwitchCase": 1, "VariableDeclarator": {"var": 0, "let": 0, "const": 0}}], //specify tab or space width for your code (fixable)
    "jsx-quotes": [2,"prefer-double"], //specify whether double or single quotes should be used in JSX attributes
    "key-spacing": [1, { "beforeColon": false, "afterColon": true }], //enforce spacing between keys and values in object literal properties
    "linebreak-style": [0, "unix"], //disallow mixed 'LF' and 'CRLF' as linebreaks
    "lines-around-comment": 1, //enforce empty lines around comments
    "max-nested-callbacks": [1, 3], //specify the maximum depth callbacks can be nested
    "new-cap": [1, { "capIsNewExceptions" : ["Map", "List"] }], //require a capital letter for constructors (except when calling the MAP function)
    "new-parens": 1, //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": 1, //disallow use of the Array constructor
    "no-continue": 1, //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-mixed-spaces-and-tabs": 2, //disallow mixed spaces and tabs for indentation (recommended)
    "no-multiple-empty-lines": [2, { "max": 2 }], //disallow multiple empty lines
    "no-negated-condition": 0, //disallow negated conditions
    "no-nested-ternary": 1, //disallow nested ternary expressions
    "no-new-object": 1, //disallow the use of the Object constructor
    "no-restricted-syntax": 1, //disallow use of certain syntax in code
    "no-spaced-func": 2, //disallow space between function identifier and application (fixable)
    "no-ternary": 0, //disallow the use of ternary operators
    "no-trailing-spaces": 1, //disallow trailing whitespace at the end of lines (fixable)
    "no-underscore-dangle": 0, //disallow dangling underscores in identifiers
    "no-unneeded-ternary": 1, //disallow the use of ternary operators when a simpler alternative exists
    "object-curly-spacing": [2, "never"], //require or disallow padding inside curly braces (fixable)
    "one-var": [1, "never"], //require or disallow one variable declaration per function
    "operator-assignment": [1, "always"], //require assignment operator shorthand where possible or prohibit it entirely
    "operator-linebreak": 1, //enforce operators to be placed before or after line breaks
    "padded-blocks":  [0, "never"], //enforce padding within blocks
    "quote-props": [1, "as-needed"], //require quotes around object literal property names
    "quotes": [2,"double"], //specify whether backticks, double or single quotes should be used (fixable)
    "require-jsdoc": 1, //Require JSDoc comment
    "semi-spacing": [2, { "before": false, "after": true }], //enforce spacing before and after semicolons
    "semi": 2, //require or disallow use of semicolons instead of ASI (fixable)
    "sort-vars": 1, //sort variables within the same declaration block

    "space-before-blocks":  [2, "always"], //require or disallow a space before blocks (fixable)
    "space-before-function-paren": [2,  {"anonymous": "always", "named": "never"}], //require or disallow a space before function opening parenthesis (fixable)
    "keyword-spacing": 2, //require a space before certain keywords (fixable)
    "space-in-parens": [0, "never"], //require or disallow spaces inside parentheses
    "space-infix-ops": 2, //require spaces around operators (fixable)
    "space-unary-ops": 2, //require or disallow spaces before/after unary operators (fixable)
    "spaced-comment": [2, "always"], //require or disallow a space immediately following the // or /* in a comment
    "wrap-regex": 1, //require regex literals to be wrapped in parentheses

    /* ECMAScript 6 */
    "arrow-body-style": 2, //require braces in arrow function body
    "arrow-parens": 0, //require parens in arrow function arguments
    "arrow-spacing": 2, //require space before/after arrow function's arrow (fixable)
    "constructor-super": 1, //verify calls of super() in constructors
    "generator-star-spacing": 2, //enforce spacing around the * in generator functions (fixable)
    "no-confusing-arrow": 0, //disallow arrow functions where a condition is expected
    "no-class-assign": 2, //disallow modifying variables of class declarations
    "no-const-assign": 2, //disallow modifying variables that are declared using const
    "no-dupe-class-members": 2, //disallow duplicate name in class members
    "no-this-before-super": 2, //disallow use of this/super before calling super() in constructors.
    "no-var": 0, //require let or const instead of var
    "object-shorthand": 0, //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": 1, //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": 1, //disallow generator functions that do not have yield

    /* Legacy */
    "max-depth": [0, 3], //specify the maximum depth that blocks can be nested
    "max-len": [1, 221, 2], //specify the maximum length of a line in your program
    "max-params":  [2, 5], // limits the number of parameters that can be used in the function declaration.
    "max-statements": [1, 200], //specify the maximum number of statement allowed in a function
    "no-bitwise": 1, //disallow use of bitwise operators
    "no-plusplus": 2,//disallow use of unary operators, ++ and --

    /* Babel */
    "babel/generator-star-spacing":[1, "after"], // Handles async/await functions correctly
    "babel/new-cap": [2, { "capIsNewExceptions" : ["Map","Router","List"] }], // Ignores capitalized decorators (@Decorator)
    "babel/object-curly-spacing": [2, "never"], // doesn't complain about export x from "mod"; or export * as x from "mod";
    "babel/object-shorthand": [0, "always"], // doesn't fail when using object spread (...obj)
    "babel/arrow-parens": 0, // Handles async functions correctly


    /* React */
    "react/display-name": [0, { "ignoreTranspilerName": false }], // Prevent missing displayName in a React component definition
    "react/forbid-prop-types": 0, // Forbid certain propTypes
    "react/jsx-boolean-value": [2, "always"], // Enforce boolean attributes notation in JSX
    "react/jsx-closing-bracket-location": 2, // Validate closing bracket location in JSX
    "react/jsx-curly-spacing": [2, "never"], // Enforce or disallow spaces inside of curly braces in JSX attributes
    "react/jsx-indent-props": 0, // Validate props indentation in JSX
    "react/jsx-max-props-per-line": [2, { "maximum": 2 }], // Limit maximum of props on a single line in JSX
    "react/jsx-no-bind": [2,{
      "ignoreRefs": false,
      "allowArrowFunctions": false,
      "allowBind": true}], // Prevent usage of .bind() and arrow functions in JSX props
    "react/jsx-no-duplicate-props": 2, // Prevent duplicate props in JSX
    "react/jsx-no-literals": 2, // Prevent usage of unwrapped JSX strings
    "react/jsx-no-undef": 2, // Disallow undeclared variables in JSX
    "react/sort-prop-types": 2, // Enforce propTypes declarations alphabetical sorting
    "react/jsx-sort-props": 2, // Enforce props alphabetical sorting
    "react/jsx-uses-react": 2, // Prevent React to be incorrectly marked as unused
    "react/jsx-uses-vars": 2, // Prevent variables used in JSX to be incorrectly marked as unused
    "react/no-danger": 2, // Prevent usage of dangerous JSX properties
    "react/no-did-mount-set-state": 2, // Prevent usage of setState in componentDidMount
    "react/no-did-update-set-state": 2, // Prevent usage of setState in componentDidUpdate
    "react/no-direct-mutation-state": 2, // Prevent direct mutation of this.state
    "react/no-multi-comp": 0, // Prevent multiple component definition per file
    "react/no-set-state": 0, // Prevent usage of setState
    "react/no-unknown-property": 2, // Prevent usage of unknown DOM property
    "react/prefer-es6-class": 2, // Prefer es6 class instead of createClass for React Components
    "react/prop-types": 2, // Prevent missing props validation in a React component definition
    "react/react-in-jsx-scope": 2, // Prevent missing React when using JSX
    "react/self-closing-comp": 2, // Prevent extra closing tags for components without children
    "react/sort-comp": 2, // Enforce component methods order
    "react/wrap-multilines": 0 // Prevent missing parentheses around multilines JSX

  }
}