.eslintrc.js

"use strict";

module.exports = {
    globals: {
        MediaPlayer: true,
        Playlist: true,
        Element: true,
        SettingsOverlay: true,
        SettingsStore: true,
        Utils: true,
        Equalizer: true,
        musicmetadata: true
    },
    env: {
        es6: true,
        browser: true,
        commonjs: true
    },
    "rules": {
        // Disallow using variables outside the blocks they are defined (especially
        // since only let and const are used, see "no-var").
        "block-scoped-var": 2,
        // Enforce one true brace style (opening brace on the same line) and avoid
        // start and end braces on the same line.
        "brace-style": [2, "1tbs", { "allowSingleLine": false }],
        // Require camel case names
        "camelcase": 2,
        // Allow trailing commas for easy list extension.  Having them does not
        // impair readability, but also not required either.
        "comma-dangle": 0,
        // Enforce spacing before and after comma
        "comma-spacing": [2, { "before": false, "after": true }],
        // Enforce one true comma style.
        "comma-style": [2, "last"],
        // Warn about cyclomatic complexity in functions.
        "complexity": [2, 35],
        // Require return statements to either always or never specify values.
        "consistent-return": 2,
        // Don't warn for inconsistent naming when capturing this (not so important
        // with auto-binding fat arrow functions).
        "consistent-this": 0,
        // Enforce curly brace conventions for all control statements.
        "curly": 2,
        // Don't require a default case in switch statements. Avoid being forced to
        // add a bogus default when you know all possible cases are handled.
        "default-case": 0,
        // Enforce dots on the next line with property name.
        "dot-location": [2, "property"],
        // Encourage the use of dot notation whenever possible.
        "dot-notation": 2,
        // Enforce newline at the end of file, with no multiple empty lines.
        "eol-last": 2,
        // Allow using == instead of ===, in the interest of landing something since
        // the devtools codebase is split on convention here.
        "eqeqeq": 0,
        // Don't require function expressions to have a name.
        // This makes the code more verbose and hard to read. Our engine already
        // does a fantastic job assigning a name to the function, which includes
        // the enclosing function name, and worst case you have a line number that
        // you can just look up.
        "func-names": 0,
        // Allow use of function declarations and expressions.
        "func-style": 0,
        // Deprecated, will be removed in 1.0.
        "generator-star": 0,
        // Enforce the spacing around the * in generator functions.
        "generator-star-spacing": [2, "after"],
        // Deprecated, will be removed in 1.0.
        "global-strict": 0,
        // Only useful in a node environment.
        "handle-callback-err": 0,
        // Tab width.
        "indent": [2, 2, { "SwitchCase": 1 }],
        // Enforces spacing between keys and values in object literal properties.
        "key-spacing": [2, { "beforeColon": false, "afterColon": true }],
        // Allow mixed 'LF' and 'CRLF' as linebreaks.
        "linebreak-style": 0,
        // Don't enforce the maximum depth that blocks can be nested. The complexity
        // rule is a better rule to check this.
        "max-depth": 0,
        // Maximum length of a line.
        "max-len": [2, 100, 2, { "ignoreUrls": true, "ignorePattern": "data:image\/|\\s*require\\s*\\(|^\\s*loader\\.lazy|-\\*-" }],
        // Maximum depth callbacks can be nested.
        "max-nested-callbacks": [2, 3],
        // Don't limit the number of parameters that can be used in a function.
        "max-params": 0,
        // Don't limit the maximum number of statement allowed in a function. We
        // already have the complexity rule that's a better measurement.
        "max-statements": 0,
        // Require a capital letter for constructors, only check if all new
        // operators are followed by a capital letter. Don't warn when capitalized
        // functions are used without the new operator.
        "new-cap": [2, { "capIsNew": false }],
        // Disallow the omission of parentheses when invoking a constructor with no
        // arguments.
        "new-parens": 2,
        // Disallow use of the Array constructor.
        "no-array-constructor": 2,
        // Allow use of bitwise operators.
        "no-bitwise": 0,
        // Disallow use of arguments.caller or arguments.callee.
        "no-caller": 2,
        // Disallow the catch clause parameter name being the same as a variable in
        // the outer scope, to avoid confusion.
        "no-catch-shadow": 2,
        // Deprecated, will be removed in 1.0.
        "no-comma-dangle": 0,
        // Disallow assignment in conditional expressions.
        "no-cond-assign": 2,
        // Allow using the console API.
        "no-console": 0,
        // Allow using constant expressions in conditions like while (true)
        "no-constant-condition": 0,
        // Allow use of the continue statement.
        "no-continue": 0,
        // Disallow control characters in regular expressions.
        "no-control-regex": 2,
        // Disallow use of debugger.
        "no-debugger": 2,
        // Disallow deletion of variables (deleting properties is fine).
        "no-delete-var": 2,
        // Allow division operators explicitly at beginning of regular expression.
        "no-div-regex": 0,
        // 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 else after a return in an if. The else around the second return
        // here is useless:
        // if (something) { return false; } else { return true; }
        "no-else-return": 2,
        // Disallow empty statements. This will report an error for:
        // try { something(); } catch (e) {}
        // but will not report it for:
        // try { something(); } catch (e) { /* Silencing the error because ...*/ }
        // which is a valid use case.
        "no-empty": 2,
        // Disallow the use of empty character classes in regular expressions.
        "no-empty-character-class": 2,
        // Disallow use of eval(). We have other APIs to evaluate code in content.
        "no-eval": 2,
        // Disallow assigning to the exception in a catch block.
        "no-ex-assign": 2,
        // Disallow adding to native types
        "no-extend-native": 2,
        // Disallow unnecessary function binding.
        "no-extra-bind": 2,
        // Disallow double-negation boolean casts in a boolean context.
        "no-extra-boolean-cast": 2,
        // Allow unnecessary parentheses, as they may make the code more readable.
        "no-extra-parens": 0,
        // Disallow unnecessary semicolons.
        "no-extra-semi": 2,
        // Deprecated, will be removed in 1.0.
        "no-extra-strict": 0,
        // Disallow fallthrough of case statements, except if there is a comment.
        "no-fallthrough": 2,
        // Allow the use of leading or trailing decimal points in numeric literals.
        "no-floating-decimal": 0,
        // Disallow comments inline after code.
        "no-inline-comments": 2,
        // Disallow if as the only statement in an else block.
        "no-lonely-if": 2,
        // Allow mixing regular variable and require declarations (not a node env).
        "no-mixed-requires": 0,
        // Disallow mixed spaces and tabs for indentation.
        "no-mixed-spaces-and-tabs": 2,
        // Disallow use of multiple spaces (sometimes used to align const values,
        // array or object items, etc.). It's hard to maintain and doesn't add that
        // much benefit.
        "no-multi-spaces": 2,
        // Disallow use of multiline strings (use template strings instead).
        "no-multi-str": 2,
        // Disallow multiple empty lines.
        "no-multiple-empty-lines": [2, { "max": 1 }],
        // Disallow reassignments of native objects.
        "no-native-reassign": 2,
        // Disallow nested ternary expressions, they make the code hard to read.
        "no-nested-ternary": 2,
        // Allow use of new operator with the require function.
        "no-new-require": 0,
        // Disallow use of octal literals.
        "no-octal": 2,
        // Allow reassignment of function parameters.
        "no-param-reassign": 0,
        // Allow string concatenation with __dirname and __filename (not a node env).
        "no-path-concat": 0,
        // Allow use of unary operators, ++ and --.
        "no-plusplus": 0,
        // Allow using process.env (not a node environment).
        "no-process-env": 0,
        // Allow using process.exit (not a node environment).
        "no-process-exit": 0,
        // Disallow usage of __proto__ property.
        "no-proto": 2,
        // Disallow declaring the same variable more than once (we use let anyway).
        "no-redeclare": 2,
        // Disallow multiple spaces in a regular expression literal.
        "no-regex-spaces": 2,
        // Allow reserved words being used as object literal keys.
        "no-reserved-keys": 0,
        // Don't restrict usage of specified node modules (not a node environment).
        "no-restricted-modules": 0,
        // Disallow use of assignment in return statement. It is preferable for a
        // single line of code to have only one easily predictable effect.
        "no-return-assign": 2,
        // Allow use of javascript: urls.
        "no-script-url": 0,
        // Disallow comparisons where both sides are exactly the same.
        "no-self-compare": 2,
        // Disallow use of comma operator.
        "no-sequences": 2,
        // Warn about declaration of variables already declared in the outer scope.
        // This isn't an error because it sometimes is useful to use the same name
        // in a small helper function rather than having to come up with another
        // random name.
        // Still, making this a warning can help people avoid being confused.
        "no-shadow": 2,
        // Disallow shadowing of names such as arguments.
        "no-shadow-restricted-names": 2,
        // Deprecated, will be removed in 1.0.
        "no-space-before-semi": 0,
        // Disallow space between function identifier and application.
        "no-spaced-func": 2,
        // Disallow sparse arrays, eg. let arr = [,,2].
        // Array destructuring is fine though:
        // for (let [, breakpointPromise] of aPromises)
        "no-sparse-arrays": 2,
        // Allow use of synchronous methods (not a node environment).
        "no-sync": 0,
        // Allow the use of ternary operators.
        "no-ternary": 0,
        // Disallow throwing literals (eg. throw "error" instead of
        // throw new Error("error")).
        "no-throw-literal": 2,
        // Disallow trailing whitespace at the end of lines.
        "no-trailing-spaces": 2,
        // Disallow use of undeclared variables unless mentioned in a /*global */
        // block. Note that globals from head.js are automatically imported in tests
        // by the import-headjs-globals rule form the mozilla eslint plugin.
        "no-undef": 2,
        // Allow dangling underscores in identifiers (for privates).
        "no-underscore-dangle": 0,
        // Allow use of undefined variable.
        "no-undefined": 0,
        // Disallow the use of Boolean literals in conditional expressions.
        "no-unneeded-ternary": 2,
        // Disallow unreachable statements after a return, throw, continue, or break
        // statement.
        "no-unreachable": 2,
        // Disallow global and local variables that aren't used, but allow unused function arguments.
        "no-unused-vars": [2, { "vars": "all", "args": "none" }],
        // Allow using variables before they are defined.
        "no-use-before-define": 0,
        // We use var-only-at-top-level instead of no-var as we allow top level
        // vars.
        "no-var": 0,
        // Allow using TODO/FIXME comments.
        "no-warning-comments": 0,
        // Disallow use of the with statement.
        "no-with": 2,
        // Require method and property shorthand syntax for object literals.
        "object-shorthand": 2,
        // Allow more than one variable declaration per function.
        "one-var": 0,
        // Disallow padding within blocks.
        "padded-blocks": [2, "never"],
        // Don't require quotes around object literal property names.
        "quote-props": 0,
        // Double quotes should be used.
        "quotes": [2, "double", "avoid-escape"],
        // Don't require use of the second argument for parseInt().
        "radix": 0,
        // Always require use of semicolons wherever they are valid.
        "semi": [2, "always"],
        // Enforce spacing after semicolons.
        "semi-spacing": [2, { "before": false, "after": true }],
        // Don't require to sort variables within the same declaration block.
        // Anyway, one-var is disabled.
        "sort-vars": 0,
        // Deprecated, will be removed in 1.0.
        "space-after-function-name": 0,
        // Require a space around all keywords.
        "keyword-spacing": 2,
        // Require a space before the start brace of a block.
        "space-before-blocks": [2, "always"],
        // Deprecated, will be removed in 1.0.
        "space-before-function-parentheses": 0,
        // Require space after keyword for anonymous functions, but disallow space
        // after name of named functions.
        "space-before-function-paren": [2, { "anonymous": "never", "named": "never" }],
        // Disable the rule that checks if spaces inside {} and [] are there or not.
        // Our code is split on conventions, and it'd be nice to have 2 rules
        // instead, one for [] and one for {}. So, disabling until we write them.
        "space-in-brackets": 0,
        // Disallow spaces inside parentheses.
        "space-in-parens": [2, "never"],
        // Require spaces around operators, except for a|0.
        "space-infix-ops": [2, { "int32Hint": true }],
        // Require spaces before/after unary operators (words on by default,
        // nonwords off by default).
        "space-unary-ops": [2, { "words": true, "nonwords": false }],
        // Deprecated, will be removed in 1.0.
        "space-unary-word-ops": 0,
        // Require a space immediately following the // in a line comment.
        "spaced-comment": [2, "always"],
        // Require "use strict" to be defined globally in the script.
        "strict": [2, "global"],
        // Disallow comparisons with the value NaN.
        "use-isnan": 2,
        // Warn about invalid JSDoc comments.
        // Disabled for now because of https://github.com/eslint/eslint/issues/2270
        // The rule fails on some jsdoc comments like in:
        // devtools/client/webconsole/console-output.js
        "valid-jsdoc": 0,
        // Ensure that the results of typeof are compared against a valid string.
        "valid-typeof": 2,
        // Allow vars to be declared anywhere in the scope.
        "vars-on-top": 0,
        // Don't require immediate function invocation to be wrapped in parentheses.
        "wrap-iife": 0,
        // Don't require regex literals to be wrapped in parentheses (which
        // supposedly prevent them from being mistaken for division operators).
        "wrap-regex": 0,
        // Disallow Yoda conditions (where literal value comes first).
        "yoda": 2,

        // And these are the rules that haven't been discussed so far, and that are
        // disabled for now until we introduce them, one at a time.

        // Require for-in loops to have an if statement.
        "guard-for-in": 0,
        // allow/disallow an empty newline after var statement
        "newline-after-var": 0,
        // disallow the use of alert, confirm, and prompt
        "no-alert": 0,
        // disallow comparisons to null without a type-checking operator
        "no-eq-null": 0,
        // disallow overwriting functions written as function declarations
        "no-func-assign": 0,
        // disallow use of eval()-like methods
        "no-implied-eval": 0,
        // disallow function or variable declarations in nested blocks
        "no-inner-declarations": 0,
        // disallow invalid regular expression strings in the RegExp constructor
        "no-invalid-regexp": 0,
        // disallow irregular whitespace outside of strings and comments
        "no-irregular-whitespace": 0,
        // disallow usage of __iterator__ property
        "no-iterator": 0,
        // disallow labels that share a name with a variable
        "no-label-var": 0,
        // disallow use of labeled statements
        "no-labels": 2,
        // disallow unnecessary nested blocks
        "no-lone-blocks": 0,
        // disallow creation of functions within loops
        "no-loop-func": 0,
        // disallow negation of the left operand of an in expression
        "no-negated-in-lhs": 0,
        // disallow use of new operator when not part of the assignment or
        // comparison
        "no-new": 0,
        // disallow use of new operator for Function object
        "no-new-func": 0,
        // disallow use of the Object constructor
        "no-new-object": 0,
        // disallows creating new instances of String,Number, and Boolean
        "no-new-wrappers": 0,
        // disallow the use of object properties of the global object (Math and
        // JSON) as functions
        "no-obj-calls": 0,
        // disallow use of octal escape sequences in string literals, such as
        // var foo = "Copyright \251";
        "no-octal-escape": 0,
        // disallow use of undefined when initializing variables
        "no-undef-init": 0,
        // disallow usage of expressions in statement position
        "no-unused-expressions": 0,
        // disallow use of void operator
        "no-void": 0,
        // disallow wrapping of non-IIFE statements in parens
        "no-wrap-func": 0,
        // 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 quote around keys
        "quote-props": ["error", "consistent-as-needed"],
    }
}