{
    "env": {
        "browser": true,
        "es6": true
    },
    "parserOptions": {
        "sourceType": "module"
    },
    "extends": "eslint:recommended",
    "rules": {
        "no-unused-vars": ["error", { "vars": "all", "args": "none", "ignoreRestSiblings": true }],
        "no-constant-condition": ["error", { "checkLoops": false }],
        "no-var": "error",
        "no-useless-constructor": "error",
        "object-shorthand": ["error", "methods", { "avoidQuotes": true }],
        "prefer-arrow-callback": "error",
        "arrow-body-style": ["error", "as-needed", { "requireReturnForObjectLiteral": false } ],
        "arrow-parens": ["error", "as-needed", { "requireForBlockBody": true }],
        "arrow-spacing": ["error"],
        "no-confusing-arrow": ["error", { "allowParens": true }],

        // enforce line breaks after opening and before closing array brackets
        // https://eslint.org/docs/rules/array-bracket-newline
        // TODO: enable? semver-major
        "array-bracket-newline": ["off", "consistent"], // object option alternative: { multiline: true, minItems: 3 }

        // enforce line breaks between array elements
        // https://eslint.org/docs/rules/array-element-newline
        // TODO: enable? semver-major
        "array-element-newline": ["off", { multiline: true, minItems: 3 }],

        // enforce spacing inside array brackets
        "array-bracket-spacing": ["error", "never"],

        // enforce spacing inside single-line blocks
        // https://eslint.org/docs/rules/block-spacing
        "block-spacing": ["error", "always"],

        // enforce one true brace style
        "brace-style": ["error", "1tbs", { allowSingleLine: true }],

        // require camel case names
        // TODO: semver-major (eslint 5): add ignoreDestructuring: false option
        // camelcase: ["error", { properties: "never" }],

        // enforce or disallow capitalization of the first letter of a comment
        // https://eslint.org/docs/rules/capitalized-comments
        "capitalized-comments": ["off", "never", {
            line: {
                ignorePattern: ".*",
                ignoreInlineComments: true,
                ignoreConsecutiveComments: true,
            },
            block: {
                ignorePattern: ".*",
                ignoreInlineComments: true,
                ignoreConsecutiveComments: true,
            },
        }],

        // require trailing commas in multiline object literals
        // "comma-dangle": ["error", {
        //     arrays: "always-multiline",
        //     objects: "always-multiline",
        //     imports: "always-multiline",
        //     exports: "always-multiline",
        //     functions: "always-multiline",
        // }],

        // enforce spacing before and after comma
        "comma-spacing": ["error", { before: false, after: true }],

        // enforce one true comma style
        "comma-style": ["error", "last", {
            exceptions: {
                ArrayExpression: false,
                ArrayPattern: false,
                ArrowFunctionExpression: false,
                CallExpression: false,
                FunctionDeclaration: false,
                FunctionExpression: false,
                ImportDeclaration: false,
                ObjectExpression: false,
                ObjectPattern: false,
                VariableDeclaration: false,
                NewExpression: false,
            }
        }],

        // disallow padding inside computed properties
        "computed-property-spacing": ["error", "never"],

        // enforces consistent naming when capturing the current execution context
        "consistent-this": "off",

        // enforce newline at the end of file, with no multiple empty lines
        "eol-last": ["error", "always"],

        // enforce spacing between functions and their invocations
        // https://eslint.org/docs/rules/func-call-spacing
        "func-call-spacing": ["error", "never"],

        // requires function names to match the name of the variable or property to which they are
        // assigned
        // https://eslint.org/docs/rules/func-name-matching
        // TODO: semver-major (eslint 5): add considerPropertyDescriptor: true
        "func-name-matching": ["off", "always", {
            includeCommonJSModuleExports: false
        }],

        // require function expressions to have a name
        // https://eslint.org/docs/rules/func-names
        // "func-names": "warn",

        // enforces use of function declarations or expressions
        // https://eslint.org/docs/rules/func-style
        // TODO: enable
        "func-style": ["off", "expression"],

        // enforce consistent line breaks inside function parentheses
        // https://eslint.org/docs/rules/function-paren-newline
        "function-paren-newline": ["error", "consistent"],

        // Blacklist certain identifiers to prevent them being used
        // https://eslint.org/docs/rules/id-blacklist
        "id-blacklist": "off",

        // this option enforces minimum and maximum identifier lengths
        // (variable names, property names etc.)
        "id-length": "off",

        // require identifiers to match the provided regular expression
        "id-match": "off",

        // Enforce the location of arrow function bodies with implicit returns
        // https://eslint.org/docs/rules/implicit-arrow-linebreak
        "implicit-arrow-linebreak": ["error", "beside"],

        // this option sets a specific tab width for your code
        // https://eslint.org/docs/rules/indent
        indent: ["error", 2, {
            SwitchCase: 1,
            VariableDeclarator: 1,
            outerIIFEBody: 1,
            // MemberExpression: null,
            FunctionDeclaration: {
                parameters: 1,
                body: 1
            },
            FunctionExpression: {
                parameters: 1,
                body: 1
            },
            CallExpression: {
                arguments: 1
            },
            ArrayExpression: 1,
            ObjectExpression: 1,
            ImportDeclaration: 1,
            flatTernaryExpressions: false,
            // list derived from https://github.com/benjamn/ast-types/blob/HEAD/def/jsx.js
            ignoredNodes: ["JSXElement", "JSXElement > *", "JSXAttribute", "JSXIdentifier", "JSXNamespacedName", "JSXMemberExpression", "JSXSpreadAttribute", "JSXExpressionContainer", "JSXOpeningElement", "JSXClosingElement", "JSXText", "JSXEmptyExpression", "JSXSpreadChild"],
            ignoreComments: false
        }],

        // specify whether double or single quotes should be used in JSX attributes
        // https://eslint.org/docs/rules/jsx-quotes
        "jsx-quotes": ["off", "prefer-double"],

        // enforces spacing between keys and values in object literal properties
        "key-spacing": ["error", { beforeColon: false, afterColon: true }],

        // require a space before & after certain keywords
        "keyword-spacing": ["error", {
            before: true,
            after: true,
            overrides: {
                return: { after: true },
                throw: { after: true },
                case: { after: true }
            }
        }],

        // enforce position of line comments
        // https://eslint.org/docs/rules/line-comment-position
        // TODO: enable?
        "line-comment-position": ["off", {
            position: "above",
            ignorePattern: "",
            applyDefaultPatterns: true,
        }],

        // disallow mixed "LF" and "CRLF" as linebreaks
        // https://eslint.org/docs/rules/linebreak-style
        "linebreak-style": ["error", "unix"],

        // require or disallow an empty line between class members
        // https://eslint.org/docs/rules/lines-between-class-members
        "lines-between-class-members": ["error", "always", { exceptAfterSingleLine: false }],

        // enforces empty lines around comments
        "lines-around-comment": "off",

        // require or disallow newlines around directives
        // https://eslint.org/docs/rules/lines-around-directive
        // "lines-around-directive": ["error", {
        //     before: "always",
        //     after: "always",
        // }],

        // specify the maximum depth that blocks can be nested
        "max-depth": ["off", 4],

        // specify the maximum length of a line in your program
        // https://eslint.org/docs/rules/max-len
        "max-len": ["error", 100, 2, {
            ignoreUrls: true,
            ignoreComments: false,
            ignoreRegExpLiterals: true,
            ignoreStrings: true,
            ignoreTemplateLiterals: true,
        }],

        // specify the max number of lines in a file
        // https://eslint.org/docs/rules/max-lines
        "max-lines": ["off", {
            max: 300,
            skipBlankLines: true,
            skipComments: true
        }],

        // enforce a maximum function length
        // https://eslint.org/docs/rules/max-lines-per-function
        "max-lines-per-function": ["off", {
            max: 50,
            skipBlankLines: true,
            skipComments: true,
            IIFEs: true,
        }],

        // specify the maximum depth callbacks can be nested
        "max-nested-callbacks": "off",

        // limits the number of parameters that can be used in the function declaration.
        "max-params": ["off", 3],

        // specify the maximum number of statement allowed in a function
        "max-statements": ["off", 10],

        // restrict the number of statements per line
        // https://eslint.org/docs/rules/max-statements-per-line
        "max-statements-per-line": ["off", { max: 1 }],

        // enforce a particular style for multiline comments
        // https://eslint.org/docs/rules/multiline-comment-style
        "multiline-comment-style": ["off", "starred-block"],

        // require multiline ternary
        // https://eslint.org/docs/rules/multiline-ternary
        // TODO: enable?
        "multiline-ternary": ["off", "never"],

        // require a capital letter for constructors
        "new-cap": ["error", {
            newIsCap: true,
            newIsCapExceptions: [],
            capIsNew: false,
            capIsNewExceptions: ["Immutable.Map", "Immutable.Set", "Immutable.List"],
        }],

        // disallow the omission of parentheses when invoking a constructor with no arguments
        // https://eslint.org/docs/rules/new-parens
        "new-parens": "error",

        // allow/disallow an empty newline after var statement
        "newline-after-var": "off",

        // https://eslint.org/docs/rules/newline-before-return
        "newline-before-return": "off",

        // enforces new line after each method call in the chain to make it
        // more readable and easy to maintain
        // https://eslint.org/docs/rules/newline-per-chained-call
        "newline-per-chained-call": ["error", { ignoreChainWithDepth: 4 }],

        // disallow use of the Array constructor
        "no-array-constructor": "error",

        // disallow use of bitwise operators
        // https://eslint.org/docs/rules/no-bitwise
        // "no-bitwise": "error",

        // disallow use of the continue statement
        // https://eslint.org/docs/rules/no-continue
        // "no-continue": "error",

        // disallow comments inline after code
        "no-inline-comments": "off",

        // disallow if as the only statement in an else block
        // https://eslint.org/docs/rules/no-lonely-if
        "no-lonely-if": "error",

        // disallow un-paren"d mixes of different operators
        // https://eslint.org/docs/rules/no-mixed-operators
        // "no-mixed-operators": ["error", {
        //     // the list of arthmetic groups disallows mixing `%` and `**`
        //     // with other arithmetic operators.
        //     groups: [
        //         ["%", "**"],
        //         ["%", "+"],
        //         ["%", "-"],
        //         ["%", "*"],
        //         ["%", "/"],
        //         ["**", "+"],
        //         ["**", "-"],
        //         ["**", "*"],
        //         ["**", "/"],
        //         ["&", "|", "^", "~", "<<", ">>", ">>>"],
        //         ["==", "!=", "===", "!==", ">", ">=", "<", "<="],
        //         ["&&", "||"],
        //         ["in", "instanceof"]
        //     ],
        //     allowSamePrecedence: false
        // }],

        // disallow mixed spaces and tabs for indentation
        "no-mixed-spaces-and-tabs": "error",

        // disallow use of chained assignment expressions
        // https://eslint.org/docs/rules/no-multi-assign
        // "no-multi-assign": ["error"],

        // disallow multiple empty lines and only one newline at the end
        "no-multiple-empty-lines": ["error", { max: 2, maxEOF: 0 }],

        // disallow negated conditions
        // https://eslint.org/docs/rules/no-negated-condition
        "no-negated-condition": "off",

        // disallow nested ternary expressions
        // "no-nested-ternary": "error",

        // disallow use of the Object constructor
        "no-new-object": "error",

        // disallow use of unary operators, ++ and --
        // https://eslint.org/docs/rules/no-plusplus
        // "no-plusplus": "error",

        // disallow certain syntax forms
        // https://eslint.org/docs/rules/no-restricted-syntax
        "no-restricted-syntax": [
            "error",
            // {
            //     selector: "ForInStatement",
            //     message: "for..in loops iterate over the entire prototype chain, which is virtually never what you want. Use Object.{keys,values,entries}, and iterate over the resulting array.",
            // },
            {
                selector: "ForOfStatement",
                message: "iterators/generators require regenerator-runtime, which is too heavyweight for this guide to allow them. Separately, loops should be avoided in favor of array iterations.",
            },
            {
                selector: "LabeledStatement",
                message: "Labels are a form of GOTO; using them makes code confusing and hard to maintain and understand.",
            },
            {
                selector: "WithStatement",
                message: "`with` is disallowed in strict mode because it makes code impossible to predict and optimize.",
            },
        ],

        // disallow space between function identifier and application
        "no-spaced-func": "error",

        // disallow tab characters entirely
        "no-tabs": "error",

        // disallow the use of ternary operators
        "no-ternary": "off",

        // disallow trailing whitespace at the end of lines
        "no-trailing-spaces": ["error", {
            skipBlankLines: false,
            ignoreComments: false,
        }],

        // disallow dangling underscores in identifiers
        // "no-underscore-dangle": ["error", {
        //     allow: [],
        //     allowAfterThis: true,
        //     allowAfterSuper: false,
        //     enforceInMethodNames: false,
        // }],

        // disallow the use of Boolean literals in conditional expressions
        // also, prefer `a || b` over `a ? a : b`
        // https://eslint.org/docs/rules/no-unneeded-ternary
        "no-unneeded-ternary": ["error", { defaultAssignment: false }],

        // disallow whitespace before properties
        // https://eslint.org/docs/rules/no-whitespace-before-property
        "no-whitespace-before-property": "error",

        // enforce the location of single-line statements
        // https://eslint.org/docs/rules/nonblock-statement-body-position
        "nonblock-statement-body-position": ["error", "beside", { overrides: {} }],

        // require padding inside curly braces
        "object-curly-spacing": ["error", "always"],

        // enforce line breaks between braces
        // https://eslint.org/docs/rules/object-curly-newline
        "object-curly-newline": ["error", {
            ObjectExpression: { minProperties: 4, multiline: true, consistent: true },
            ObjectPattern: { minProperties: 4, multiline: true, consistent: true },
            ImportDeclaration: { minProperties: 4, multiline: true, consistent: true },
            ExportDeclaration: { minProperties: 4, multiline: true, consistent: true },
        }],

        // enforce "same line" or "multiple line" on object properties.
        // https://eslint.org/docs/rules/object-property-newline
        "object-property-newline": ["error", {
            allowAllPropertiesOnSameLine: true,
        }],

        // allow just one var statement per function
        "one-var": ["error", "never"],

        // require a newline around variable declaration
        // https://eslint.org/docs/rules/one-var-declaration-per-line
        "one-var-declaration-per-line": ["error", "always"],

        // require assignment operator shorthand where possible or prohibit it entirely
        // https://eslint.org/docs/rules/operator-assignment
        "operator-assignment": ["error", "always"],

        // Requires operator at the beginning of the line in multiline statements
        // https://eslint.org/docs/rules/operator-linebreak
        "operator-linebreak": ["error", "before", { overrides: { "=": "none" } }],

        // disallow padding within blocks
        "padded-blocks": ["error", { blocks: "never", classes: "never", switches: "never" }],

        // Require or disallow padding lines between statements
        // https://eslint.org/docs/rules/padding-line-between-statements
        "padding-line-between-statements": "off",

        // Prefer use of an object spread over Object.assign
        // https://eslint.org/docs/rules/prefer-object-spread
        // TODO: semver-major (eslint 5): enable
        "prefer-object-spread": "off",

        // require quotes around object literal property names
        // https://eslint.org/docs/rules/quote-props.html
        "quote-props": ["error", "as-needed", { keywords: false, unnecessary: true, numbers: false }],

        // specify whether double or single quotes should be used
        quotes: ["error", "single", { avoidEscape: true }],

        // do not require jsdoc
        // https://eslint.org/docs/rules/require-jsdoc
        "require-jsdoc": "off",

        // require or disallow use of semicolons instead of ASI
        semi: ["error", "always"],

        // enforce spacing before and after semicolons
        "semi-spacing": ["error", { before: false, after: true }],

        // Enforce location of semicolons
        // https://eslint.org/docs/rules/semi-style
        "semi-style": ["error", "last"],

        // requires object keys to be sorted
        "sort-keys": ["off", "asc", { caseSensitive: false, natural: true }],

        // sort variables within the same declaration block
        "sort-vars": "off",

        // require or disallow space before blocks
        "space-before-blocks": "error",

        // require or disallow space before function opening parenthesis
        // https://eslint.org/docs/rules/space-before-function-paren
        "space-before-function-paren": ["error", {
            anonymous: "always",
            named: "never",
            asyncArrow: "always"
        }],

        // require or disallow spaces inside parentheses
        "space-in-parens": ["error", "never"],

        // require spaces around operators
        "space-infix-ops": "error",

        // Require or disallow spaces before/after unary operators
        // https://eslint.org/docs/rules/space-unary-ops
        "space-unary-ops": ["error", {
            words: true,
            nonwords: false,
            overrides: {
            },
        }],

        // require or disallow a space immediately following the // or /* in a comment
        // https://eslint.org/docs/rules/spaced-comment
        "spaced-comment": ["error", "always", {
            line: {
                exceptions: ["-", "+"],
                markers: ["=", "!"], // space here to support sprockets directives
            },
            block: {
                exceptions: ["-", "+"],
                markers: ["=", "!"], // space here to support sprockets directives
                balanced: true,
            }
        }],

        // Enforce spacing around colons of switch statements
        // https://eslint.org/docs/rules/switch-colon-spacing
        "switch-colon-spacing": ["error", { after: true, before: false }],

        // Require or disallow spacing between template tags and their literals
        // https://eslint.org/docs/rules/template-tag-spacing
        "template-tag-spacing": ["error", "never"],

        // require or disallow the Unicode Byte Order Mark
        // https://eslint.org/docs/rules/unicode-bom
        "unicode-bom": ["error", "never"],

        // require regex literals to be wrapped in parentheses
        "wrap-regex": "off"
    }
}