.eslintrc.json

{
  "extends": "react-app",
  "rules": {
    // require default case in switch statements
    "default-case": 2,
    // require the use of === and !==
    "eqeqeq": 2,
    // disallow unnecessary function binding
    "no-extra-bind": 2,
    // disallow use of multiple spaces
    "no-multi-spaces": 2,
    // disallow reassignment of function parameters
    "no-param-reassign": 2,
    // disallow usage of __proto__ property
    "no-proto": 2,
    // disallow declaring the same variable more then once
    "no-redeclare": 2,
    // require use of the second argument for parseInt()
    "radix": 2,
    // requires to declare all vars on top of their containing scope
    "vars-on-top": 2,
    // require immediate function invocation to be wrapped in parentheses
    "wrap-iife": [2, "any"],
    // require or disallow Yoda conditions
    "yoda": 2,
    // disallow duplicate arguments in functions
    "no-dupe-args": 2,

    // disallow duplicate keys when creating object literals
    "no-dupe-keys": 2,
    // disallow empty statements
    "no-empty": 2,
    // disallow invalid regular expression strings in the RegExp constructor
    "no-invalid-regexp": 2,
    // disallow irregular whitespace outside of strings and comments
    "no-irregular-whitespace": 2,

    // ensure that the results of typeof are compared against a valid string
    "valid-typeof": 2,

    // require space before/after arrow function's arrow
    "arrow-spacing": 2,

    // disallow modifying variables that are declared using const
    "no-const-assign": 2,

    // require let or const instead of var
    "no-var": 2,

    // suggest using of const declaration for variables that are never modified after declared
    "prefer-const": 2,

    // suggest using the spread operator instead of .apply()
    "prefer-spread": 2,

    // disallow use of undeclared variables unless mentioned in a /*global */ block
    "no-undef": 2,
    // disallow declaration of variables that are not used in the code
    "no-unused-vars": [2, {
      "vars": "local",
      "args": "after-used"
    }],

    // Enforce boolean attributes notation in JSX
    "react/jsx-boolean-value": 2,

    // Ensure correct position of the first property
    "react/jsx-first-prop-new-line": [2, "multiline"],

    // Validates a specific indentation style for props
    "react/jsx-indent-props": [2, 2],

    // Checks all JSX elements and verifies the number of props per line
    "react/jsx-max-props-per-line": [2, {
      "maximum": 2
    }],

    // Disallow undeclared variables in JSX
    "react/jsx-no-undef": 2,

    // Prevent React to be incorrectly marked as unused
    "react/jsx-uses-react": 2,
    // Prevent variables used in JSX to be incorrectly marked as unused
    "react/jsx-uses-vars": 2,

    // Prevent usage of setState in componentDidMount
    "react/no-did-mount-set-state": [2],
    // Prevent usage of setState in componentDidUpdate
    "react/no-did-update-set-state": 2,
    // Prevent direct mutation of this.state
    "react/no-direct-mutation-state": 2,
    // Prevent multiple component definition per file
    "react/no-multi-comp": [2, {
      "ignoreStateless": true
    }],

    // Enforce ES6 classes for React Components
    "react/prefer-es6-class": 2,
    // Enforce stateless React Components to be written as a pure function
    "react/prefer-stateless-function": 2,
    // Prevent missing props validation in a React component definition
    "react/prop-types": 2,
    // Prevent missing React when using JSX
    "react/react-in-jsx-scope": 2,

    // Enforce component methods order
    "react/sort-comp": [2, {
      "order": [
        "propTypes",
        "defaultProps",
        "contextTypes",
        "state",
        "displayName",
        "getInitialState",
        "constructor",
        "static-methods",
        "componentWillMount",
        "componentDidMount",
        "componentWillReceiveProps",
        "shouldComponentUpdate",
        "componentWillUpdate",
        "componentDidUpdate",
        "componentWillUnmount",
        "/^on.+$/",
        "everything-else",
        "/^render.+$/",
        "render"
      ]
    }],
    // Prevent missing parentheses around multilines JSX
    "react/jsx-wrap-multilines": 2,

    /*STYLING*/
    // enforce spacing inside array brackets
    "array-bracket-spacing": [2, "never"],
    // enforce one true brace style
    "brace-style": [2, "1tbs", {"allowSingleLine": true }],
    // require camel case names
    "camelcase": [2, {"properties": "never"}],
    // enforce spacing before and after comma
    "comma-spacing": [2, {"before": false, "after": true}],
    // enforce one true comma style
    "comma-style": [2, "last"],
    // disallow padding inside computed properties
    "computed-property-spacing": [2, "never"],
    // this option sets a specific tab width for your code
    "indent": [2, 2, { "SwitchCase": 1 }],
    // specify whether double or single quotes should be used in JSX attributes
    "jsx-quotes": 2,
    // enforces spacing between keys and values in object literal properties
    "key-spacing": [2, {"beforeColon": false, "afterColon": true}],
    // require a space before & after certain keywords
    "keyword-spacing": 2,
    // disallow mixed spaces and tabs for indentation
    "no-mixed-spaces-and-tabs": 2,
    // disallow multiple empty lines and only one newline at the end
    "no-multiple-empty-lines": [2, {"max": 2}],
    // disallow use of the Object constructor
    "no-new-object": 2,
    // disallow space between function identifier and application
    "no-spaced-func": 2,
    // disallow trailing whitespace at the end of lines
    "no-trailing-spaces": 2,
    // require padding inside curly braces
    "object-curly-spacing": [2, "always"],
    // allow just one var statement per function
    "one-var": [2, "never"],
    // enforce padding within blocks
    "padded-blocks": [2, "never"],
    // require quotes around object literal property names
    "quote-props": ["error", "consistent-as-needed"],
    // specify whether double or single quotes should be used
    "quotes": [2, "single", "avoid-escape"],
    // enforce spacing before and after semicolons
    "semi-spacing": [2, {"before": false, "after": true}],
    // require or disallow use of semicolons instead of ASI
    "semi": [2, "always"],
    // require or disallow space before blocks
    "space-before-blocks": 2,
    // require or disallow space before function opening parenthesis
    "space-before-function-paren": [2, "never"],
    // disallow spaces inside parentheses
    "space-in-parens": [2, "never"],
    // require spaces around operators
    "space-infix-ops": 2,
    // require or disallow a space immediately following the // or /* in a comment
    "spaced-comment": [2, "always", {
      "exceptions": ["-", "+"],
      "markers": ["=", "!"]           // space here to support sprockets directives
    }]
  }
}