.eslintrc

// Rules reference: http://eslint.org/docs/rules/
{
  "extends": [],
  "env": {
    "browser": true,
    "node" : true,
    "es6": true,
    "mocha": true
  },

  "globals": {
    "expect": true,
    "sinon": true,
    "module":true,
    "Snap":true,
    "_":true,
    "$":true,
    "require":true
  },

    "parserOptions": {
        "ecmaVersion": 2017,
        "sourceType": "module",
        // ES6 Language Features
        "ecmaFeatures": {
            "arrowFunctions": true,
            "blockBindings": true,
            "classes": true,
            "defaultParams": true,
            "destructuring": true,
            "forOf": true,
            "generators": true,
            "modules": true,
            "objectLiteralComputedProperties": true,
            "objectLiteralDuplicateProperties": false,
            "objectLiteralShorthandMethods": true,
            "objectLiteralShorthandProperties": true,
            "restParams": true,
            "spread": true,
            "superInFunctions": false,
            "templateStrings": true,
        }
    },

  "rules": {

    //=========================================================================
    //==================== Possible Errors ====================================
    //=========================================================================

    // disallow trailing commas in object literals
    "comma-dangle": [2, "always-multiline"], //TODO: need discussion
    // disallow assignment in conditional expressions
    "no-cond-assign": [2, "always"],
    // disallow use of console
    "no-console": 1,
    // disallow use of constant expressions in conditions
    "no-constant-condition": [2, { "checkLoops": false }],
    // disallow control characters in regular expressions
    "no-control-regex": 2,
    // disallow use of debugger
    "no-debugger": 2,
    // disallow duplicate arguments in functions
    "no-dupe-args": 2,
    // disallow duplicate keys when creating object literals
    "no-dupe-keys": 2,
    // disallow a duplicate case label.
    "no-duplicate-case": 2,
    // disallow the use of empty character classes in regular expressions
    "no-empty-character-class": 2,
    // disallow empty statements
    "no-empty": 2,
    // disallow assigning to the exception in a catch block
    "no-ex-assign": 2,
    // disallow double-negation boolean casts in a boolean context
    "no-extra-boolean-cast": 2,
    // disallow unnecessary parentheses
    "no-extra-parens": [2, "functions"],
    // disallow unnecessary semicolons
    "no-extra-semi": 2,
    // disallow overwriting functions written as function declarations
    "no-func-assign": 2,
    // disallow function or variable declarations in nested blocks
    "no-inner-declarations": 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,
    // disallow negation of the left operand of an in expression
    "no-negated-in-lhs": 2,
    // disallow the use of object properties of the global object (Math and JSON) as functions
    "no-obj-calls": 2,
    // disallow multiple spaces in a regular expression literal
    "no-regex-spaces": 2,
    // disallow sparse arrays
    "no-sparse-arrays": 2,
    // Avoid code that looks like two expressions but is actually one
    "no-unexpected-multiline": 2,
    // disallow unreachable statements after a return, throw, continue, or break statement
    "no-unreachable": 2,
    // disallow comparisons with the value NaN
    "use-isnan": 2,
    // ensure JSDoc comments are valid
    "valid-jsdoc": [2, {
      "requireReturn": false,
      "requireReturnDescription": false
    }],
    // ensure that the results of typeof are compared against a valid string
    "valid-typeof": 2,

    //=========================================================================
    //==================== Best Practices =====================================
    //=========================================================================
    // Enforces getter/setter pairs in objects
    "accessor-pairs": 2,
    // treat var statements as if they were block scoped
    "block-scoped-var": 2,
    // specify the maximum cyclomatic complexity allowed in a program
    "complexity": [0, 11],
    // require return statements to either always or never specify values
    "consistent-return": 2,
    // specify curly brace conventions for all control statements
    "curly": [2, "multi-line"],
    // require default case in switch statements
    "default-case": 2,
    // encourages use of dot notation whenever possible
    "dot-notation": [2, { "allowKeywords": true}],
    // enforces consistent newlines before or after dots
    "dot-location": [2, "property"],
    // require the use of === and !==
    "eqeqeq": 2,
    // make sure for-in loops have an if statement
    "guard-for-in": 2,
    // disallow the use of alert, confirm, and prompt
    "no-alert": 2,
    // disallow use of arguments.caller or arguments.callee
    "no-caller": 2,
    // disallow lexical declarations in case clauses
    "no-case-declarations": 2,
    // disallow division operators explicitly at beginning of regular expression
    "no-div-regex": 2,
    // disallow else after a return in an if
    "no-else-return": 2,
    // disallow use of empty destructuring patterns
    "no-empty-pattern": 2,
    // disallow comparisons to null without a type-checking operator
    "no-eq-null": 2,
    // disallow use of eval()
    "no-eval": 2,
    // disallow adding to native types
    "no-extend-native": 2,
    // disallow unnecessary function binding
    "no-extra-bind": 2,
    // disallow fallthrough of case statements
    "no-fallthrough": 2,
    // disallow the use of leading or trailing decimal points in numeric literals
    "no-floating-decimal": 2,
    // disallow the type conversions with shorter notations
    "no-implicit-coercion": 2,
    // disallow use of eval()-like methods
    "no-implied-eval": 2,
    // disallow this keywords outside of classes or class-like objects
    "no-invalid-this":0,
    // disallow usage of __iterator__ property
    "no-iterator": 2,
    // disallow use of labeled statements
    "no-labels": 2,
    // disallow unnecessary nested blocks
    "no-lone-blocks": 2,
    // disallow creation of functions within loops
    "no-loop-func": 2,
    // disallow the use of magic numbers
    "no-magic-numbers": 0, //TODO: need discussion
    // disallow use of multiple spaces
    "no-multi-spaces": 2,
    // disallow use of multiline strings
    "no-multi-str": 2,
    // disallow reassignments of native objects
    "no-native-reassign": 2,
    // disallow use of new operator for Function object
    "no-new-func": 2,
    // disallows creating new instances of String,Number, and Boolean
    "no-new-wrappers": 2,
    // disallow use of new operator when not part of the assignment or comparison
    "no-new": 2,
    // disallow use of octal escape sequences in string literals, such as
    // var foo = "Copyright \251";
    "no-octal-escape": 2,
    // disallow use of (old style) octal literals
    "no-octal": 2,
    // disallow reassignment of function parameters
    "no-param-reassign": 2,
    // disallow use of process.env
    "no-process-env": 2,
    // disallow usage of __proto__ property
    "no-proto": 2,
    // disallow declaring the same variable more then once
    "no-redeclare": 2,
    // disallow use of assignment in return statement
    "no-return-assign": 2,
    // disallow use of `javascript:` urls.
    "no-script-url": 2,
    // disallow comparisons where both sides are exactly the same
    "no-self-compare": 2,
    // disallow use of comma operator
    "no-sequences": 2,
    // restrict what can be thrown as an exception
    "no-throw-literal": 0,
    // disallow usage of expressions in statement position
    "no-unused-expressions": 2,
    // disallow unnecessary .call() and .apply()
    "no-useless-call": 2,
    // disallow unnecessary concatenation of literals or template literals
    "no-useless-concat": 2,
    // disallow use of void operator
    "no-void": 2,
    // disallow usage of configurable warning terms in comments: e.g. todo
    "no-warning-comments": [1, { "terms": ["todo", "fixme", "xxx"], "location": "start" }],
    // disallow use of the with statement
    "no-with": 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": 0,
    // require immediate function invocation to be wrapped in parentheses
    "wrap-iife": [2, "any"],
    // require or disallow Yoda conditions
    "yoda": 2,

    // //=========================================================================
    // //==================== Strict Mode ========================================
    // //=========================================================================
    // require that all functions are run in strict mode
    // "strict": [2, "global"],
    //
    //=========================================================================
    //==================== Variables ==========================================
    //=========================================================================
    // enforce or disallow variable initializations at definition
    "init-declarations": 0,
    // disallow the catch clause parameter name being the same as a variable in the outer scope
    "no-catch-shadow": 0,
    // disallow deletion of variables
    "no-delete-var": 2,
    // disallow labels that share a name with a variable
    "no-label-var": 2,
    // disallow shadowing of names such as arguments
    "no-shadow-restricted-names": 2,
    // disallow declaration of variables already declared in the outer scope
    "no-shadow": 2,
    // disallow use of undefined when initializing variables
    "no-undef-init": 0,
    // disallow use of undeclared variables unless mentioned in a /*global */ block
    "no-undef": 2,
    // disallow use of undefined variable
    "no-undefined": 0,
    // disallow declaration of variables that are not used in the code
    "no-unused-vars": [1, {"vars": "local", "args": "after-used"}],
    // disallow use of variables before they are defined
    "no-use-before-define": 2,

    //=========================================================================
    //==================== Node.js ============================================
    //=========================================================================
    // enforce return after a callback
    "callback-return": 0,
    // disallow require() outside of the top-level module scope
    "global-require": 2,
    // enforces error handling in callbacks (node environment)
    "handle-callback-err": 2,
    // disallow mixing regular variable and require declarations
    "no-mixed-requires": 2,
    // disallow use of new operator with the require function
    "no-new-require": 2,
    // disallow string concatenation with __dirname and __filename
    "no-path-concat": 1,
    // disallow process.exit()
    "no-process-exit": 2,
    // restrict usage of specified node modules
    "no-restricted-modules": 0,
    // disallow use of synchronous methods (off by default)
    "no-sync": 0,

    //=========================================================================
    //==================== Stylistic Issues ===================================
    //=========================================================================
    // enforce spacing inside array brackets
    "array-bracket-spacing": 0,
    // disallow or enforce spaces inside of single line blocks
    "block-spacing": 1,
    // enforce one true brace style
    "brace-style": [1, "1tbs", {"allowSingleLine": true }],
    // require camel case names
    "camelcase": [1, {"properties": "always"}],
    // enforce spacing before and after comma
    "comma-spacing": [1, {"before": false, "after": true}],
    // enforce one true comma style
    "comma-style": [1, "last"],
    // require or disallow padding inside computed properties
    "computed-property-spacing": 0,
    // enforces consistent naming when capturing the current execution context
    "consistent-this": 0,
    // enforce newline at the end of file, with no multiple empty lines
    "eol-last": 1,
    // require function expressions to have a name
    "func-names": 0,
    // enforces use of function declarations or expressions
    "func-style": 0,
    // this option enforces minimum and maximum identifier lengths (variable names, property names etc.)
    "id-length": 0,
    // require identifiers to match the provided regular expression
    "id-match": 0,
    // this option sets a specific tab width for your code
    "indent": [1, 4, {"SwitchCase": 1}],
    // specify whether double or single quotes should be used in JSX attributes
    "jsx-quotes": [1, "prefer-double"],
    // enforces spacing between keys and values in object literal properties
    "key-spacing": [1, {"beforeColon": false, "afterColon": true}],
    // disallow mixed "LF" and "CRLF" as linebreaks
    "linebreak-style": 0,
    // enforces empty lines around comments
    "lines-around-comment": 0,
    // specify the maximum depth that blocks can be nested
    "max-depth": [0, 4],
    // specify the maximum length of a line in your program
    "max-len": [0, 80, 4],
    // specify the maximum depth callbacks can be nested
    "max-nested-callbacks": 0,
    // limits the number of parameters that can be used in the function declaration.
    "max-params": [0, 3],
    // specify the maximum number of statement allowed in a function
    "max-statements": [0, 10],
    // require a capital letter for constructors
    "new-cap": [1, {"newIsCap": true}],
    // disallow the omission of parentheses when invoking a constructor with no arguments
    "new-parens": 0,
    // allow/disallow an empty newline after var statement
    "newline-after-var": 0,
    // disallow use of the Array constructor
    "no-array-constructor": 0,
    // disallow use of bitwise operators
    "no-bitwise": 0,
    // disallow use of the continue statement
    "no-continue": 0,
    // disallow comments inline after code
    "no-inline-comments": 0,
    // disallow if as the only statement in an else block
    "no-lonely-if": 0,
    // disallow mixed spaces and tabs for indentation
    "no-mixed-spaces-and-tabs": 1,
    // disallow multiple empty lines
    "no-multiple-empty-lines": [1, {"max": 2, "maxEOF": 1}],
    // disallow negated conditions
    "no-negated-condition": 0,
    // disallow nested ternary expressions
    "no-nested-ternary": 1,
    // disallow use of the Object constructor
    "no-new-object": 1,
    // disallow use of unary operators, ++ and --
    "no-plusplus": 0,
    // disallow use of certain syntax in code
    "no-restricted-syntax": 0,
    // disallow space between function identifier and application
    "no-spaced-func": 1,
    // disallow the use of ternary operators
    "no-ternary": 0,
    // disallow trailing whitespace at the end of lines
    "no-trailing-spaces": 1,
    // disallow dangling underscores in identifiers
    "no-underscore-dangle": 0,
    // disallow the use of Boolean literals in conditional expressions
    "no-unneeded-ternary": 0,
    // require or disallow padding inside curly braces
    "object-curly-spacing": 0,
    // allow just one var statement per function
    "one-var": [1, "never"],
    // require assignment operator shorthand where possible or prohibit it entirely
    "operator-assignment": 0,
    // enforce operators to be placed before or after line breaks
    "operator-linebreak": 0,
    // enforce padding within blocks
    "padded-blocks": [1, "never"],
    // require quotes around object literal property names
    "quote-props": 0,
    // specify whether double or single quotes should be used
    "quotes": [1, "single", "avoid-escape"],
    // Require JSDoc comment
    "require-jsdoc": 0,
    // enforce spacing before and after semicolons
    "semi-spacing": [1, {"before": false, "after": true}],
    // require or disallow use of semicolons instead of ASI
    "semi": [1, "always"],
    // sort variables within the same declaration block
    "sort-vars": 0,
    // require a space after certain keywords
    "keyword-spacing": 1,
    // require or disallow space before blocks
    "space-before-blocks": 1,
    // require or disallow space before function opening parenthesis
    "space-before-function-paren": [0, {"anonymous": "always", "named": "never"}],
    // require or disallow space before blocks
    "space-in-parens": 0,
    // require spaces around operators
    "space-infix-ops": 1,
    // Require or disallow spaces before/after unary operators
    "space-unary-ops": 0,
    // require or disallow a space immediately following the // or /* in a comment
    "spaced-comment": [1, "always", {
      "exceptions": ["-", "+", "/", "="],
      "markers": ["=", "!"]     // space here to support sprockets directives
    }],
    // require regex literals to be wrapped in parentheses
    "wrap-regex": 0,

    //=========================================================================
    //==================== ES6 Rules ==========================================
    //=========================================================================
    "arrow-body-style": [1, "as-needed"],
    // require parens in arrow function arguments
    "arrow-parens": [1, "as-needed"],
    // require space before/after arrow function"s arrow
    "arrow-spacing": 1,
    // verify super() callings in constructors
    "constructor-super": 1,
    // enforce the spacing around the * in generator functions
    "generator-star-spacing": 1,
    // disallow arrow functions where a condition is expected
    "no-confusing-arrow": 1,
    // disallow modifying variables of class declarations
    "no-class-assign": 1,
    // disallow modifying variables that are declared using const
    "no-const-assign": 1,
    // disallow duplicate name in class members
    "no-dupe-class-members": 1,
    // disallow to use this/super before super() calling in constructors.
    "no-this-before-super": 1,
    // require let or const instead of var
    "no-var": 0, //TODO: enable on full migration to es6
    // require method and property shorthand syntax for object literals
    "object-shorthand": 0,
    // suggest using arrow functions as callbacks
    "prefer-arrow-callback": 0, //TODO: enable on full migration to es6
    // suggest using of const declaration for variables that are never modified after declared
    "prefer-const": 0, //TODO: enable on full migration to es6
    // suggest using Reflect methods where applicable
    "prefer-reflect": 0,
    // suggest using the spread operator instead of .apply()
    "prefer-spread": 0,
    // suggest using template literals instead of strings concatenation
    "prefer-template": 0, //TODO: enable on full migration to es6
    // disallow generator functions that do not have yield
    "require-yield": 0
  }
}