teammates-eslint.yml

env:
    browser: true
    jquery: true
    qunit: true
rules:

    #################################################################################
    # This ruleset includes all the rules given in http://eslint.org/docs/rules/,
    # except for the NodeJS and ECMAScript 6 rules due to their irrelevance.
    # All rules recommended by ESLint are activated.
    #
    # Further consultations are made with Airbnb and Google configs, and
    # the rules recommended by them are mostly included, deactivated only when
    # the rules are not compatible with our workflow.
    #################################################################################

    # Possible Errors

    # disallow assignment operators in conditional expressions
    no-cond-assign: ["error", "except-parens"]

    # disallow the use of console
    no-console: "error"

    # disallow constant expressions in conditions
    no-constant-condition: "error"

    # disallow control characters in regular expressions
    no-control-regex: "error"

    # disallow the use of debugger
    no-debugger: "error"

    # disallow duplicate arguments in function definitions
    no-dupe-args: "error"

    # disallow duplicate keys in object literals
    no-dupe-keys: "error"

    # disallow duplicate case labels
    no-duplicate-case: "error"

    # disallow empty character classes in regular expressions
    no-empty-character-class: "error"

    # disallow empty block statements
    no-empty: "error"

    # disallow reassigning exceptions in catch clauses
    no-ex-assign: "error"

    # disallow unnecessary boolean casts
    no-extra-boolean-cast: "error"

    # disallow unnecessary parentheses
    no-extra-parens: "error"

    # disallow unnecessary semicolons
    no-extra-semi: "error"

    # disallow reassigning function declarations
    no-func-assign: "error"

    # disallow function or var declarations in nested blocks
    no-inner-declarations: "error"

    # disallow invalid regular expression strings in RegExp constructors
    no-invalid-regexp: "error"

    # disallow irregular whitespace outside of strings and comments
    no-irregular-whitespace: "error"

    # disallow calling global object properties as functions
    no-obj-calls: "error"

    # Disallow use of Object.prototypes builtins directly
    # no-prototype-builtins: "off"

    # disallow multiple spaces in regular expression literals
    no-regex-spaces: "error"

    # disallow sparse arrays
    no-sparse-arrays: "error"

    # Disallow template literal placeholder syntax in regular strings
    # no-template-curly-in-string: "off"

    # disallow confusing multiline expressions
    no-unexpected-multiline: "error"

    # disallow unreachable code after return, throw, continue, and break statements
    no-unreachable: "error"

    # disallow control flow statements in finally blocks
    no-unsafe-finally: "error"

    # disallow negating the left operand of relational operators
    no-unsafe-negation: "error"

    # require calls to isNaN() when checking for NaN
    use-isnan: "error"

    # enforce valid JSDoc comments
    valid-jsdoc: "off" # recommended by Google

    # enforce comparing typeof expressions against valid strings
    valid-typeof: "error"

    # Best Practices

    # enforce getter and setter pairs in objects
    # accessor-pairs: "off"

    # enforce return statements in callbacks of array methods
    # array-callback-return: "off"

    # enforce the use of variables within the scope they are defined
    block-scoped-var: "error"

    # enforce that class methods utilize this
    # class-methods-use-this: "off"

    # enforce a maximum cyclomatic complexity allowed in a program
    # complexity: "off"

    # require return statements to either always or never specify values
    consistent-return: "off" # recommended by Airbnb

    # enforce consistent brace style for all control statements
    curly: "error"

    # require default cases in switch statements
    default-case: "error"

    # enforce consistent newlines before and after dots
    dot-location: ["error", "property"]

    # enforce dot notation whenever possible
    dot-notation: "error"

    # require the use of === and !==
    eqeqeq: "error"

    # require for-in loops to include an if statement
    guard-for-in: "error"

    # disallow the use of alert, confirm, and prompt
    no-alert: "error"

    # disallow the use of arguments.caller or arguments.callee
    # no-caller: "off"

    # disallow lexical declarations in case clauses
    no-case-declarations: "error"

    # disallow division operators explicitly at the beginning of regular expressions
    # no-div-regex: "off"

    # disallow else blocks after return statements in if statements
    no-else-return: "error"

    # disallow empty functions
    no-empty-function: "error"

    # disallow empty destructuring patterns
    no-empty-pattern: "error"

    # disallow null comparisons without type-checking operators
    no-eq-null: "error"

    # disallow the use of eval()
    no-eval: "error"

    # disallow extending native types
    no-extend-native: "error"

    # disallow unnecessary calls to .bind()
    # no-extra-bind: "off"

    # disallow unnecessary labels
    # no-extra-label: "off"

    # disallow fallthrough of case statements
    no-fallthrough: "error"

    # disallow leading or trailing decimal points in numeric literals
    # no-floating-decimal: "off"

    # disallow assignments to native objects or read-only global variables
    no-global-assign: "error"

    # no-return-await
    # no-return-await: "off"

    # disallow shorthand type conversions
    no-implicit-coercion: "error"

    # disallow var and named function declarations in the global scope
    # no-implicit-globals: "off"

    # disallow use of eval()-like methods
    # no-implied-eval: "off"

    # disallow this keywords outside of classes or class-like objects
    # no-invalid-this: "off"

    # disallow the use of the __iterator__ property
    # no-iterator: "off"

    # disallow labeled statements
    # no-labels: "off"

    # disallow unnecessary nested blocks
    # no-lone-blocks: "off"

    # disallow function declarations and expressions inside loop statements
    no-loop-func: "off" # recommended by Airbnb and Google

    # disallow magic numbers
    # no-magic-numbers: "off"

    # disallow multiple spaces
    no-multi-spaces: "error"

    # disallow multiline strings
    # no-multi-str: "off"

    # disallow new operators with the Function object
    no-new-func: "error"

    # disallow new operators with the String, Number, and Boolean objects
    no-new-wrappers: "error"

    # disallow new operators outside of assignments or comparisons
    no-new: "error"

    # disallow octal escape sequences in string literals
    # no-octal-escape: "off"

    # disallow octal literals
    no-octal: "error"

    # disallow reassigning function parameters
    no-param-reassign: ["error", { "props": false }]

    # disallow usage of __proto__ property
    # no-proto: "off"

    # disallow var redeclaration
    no-redeclare: "error"

    # disallow certain properties on certain objects
    # no-restricted-properties: "off"

    # disallow assignment operators in return statements
    # no-return-assign: "off"

    # disallow unnecessary return await
    # no-return-await: "off"

    # disallow javascript: urls
    # no-script-url: "off"

    # disallow assignments where both sides are exactly the same
    no-self-assign: "error"

    # disallow comparisons where both sides are exactly the same
    # no-self-compare: "off"

    # disallow comma operators
    # no-sequences: "off"

    # disallow throwing literals as exceptions
    no-throw-literal: "error"

    # disallow unmodified loop conditions
    # no-unmodified-loop-condition: "off"

    # disallow unused expressions
    no-unused-expressions: "error"

    # disallow unused labels
    no-unused-labels: "error"

    # disallow unnecessary calls to .call() and .apply()
    no-useless-call: "error"

    # disallow unnecessary concatenation of literals or template literals
    no-useless-concat: "error"

    # disallow unnecessary escape characters
    no-useless-escape: "error"

    # disallow redundant return statements
    no-useless-return: "error"

    # disallow void operators
    # no-void: "off"

    # disallow specified warning terms in comments
    no-warning-comments: "off" # recommended by Google

    # disallow with statements
    # no-with: "off"

    # enforce the consistent use of the radix argument when using parseInt()
    radix: "off" # recommended by Airbnb and Google

    # disallow async functions which have no await expression
    # require-await: "off"

    # require var declarations be placed at the top of their containing scope
    vars-on-top: "off" # recommended by Airbnb

    # require parentheses around immediate function invocations
    wrap-iife: "off" # recommended by Airbnb

    # require or disallow Yoda conditions
    # yoda: "off"

    # Strict Mode

    # require or disallow strict mode directives
    strict: "off" # recommended by Airbnb

    # Variables

    # require or disallow initialization in var declarations
    # init-declarations: "off"

    # disallow catch clause parameters from shadowing variables in the outer scope
    # no-catch-shadow: "off"

    # disallow deletion of variables
    no-delete-var: "error"

    # disallow labels that share a name with a variable
    # no-label-var: "off"

    # disallow specified global variables
    # no-restricted-globals: "off"

    # disallow identifiers from shadowing restricted names
    # no-shadow-restricted-names: "off"

    # disallow declaration of variables already declared in the outer scope
    no-shadow: "off" # recommended by Airbnb

    # disallow initializing variables to undefined
    no-undef-init: "error"

    # disallow the use of undeclared variables unless mentioned in /*global */ comments
    no-undef: "off" # recommended by ESLint, Airbnb, and Google

    # disallow the use of undefined as an identifier
    no-undefined: "off" # recommended by Airbnb

    # disallow unused variables
    no-unused-vars: ["error", "local"]

    # disallow use of variables before they are defined
    no-use-before-define: "off" # recommended by Airbnb and Google

    # Stylistic Issues

    # enforce consistent spacing inside array brackets
    array-bracket-spacing: "error"

    # enforce consistent spacing inside single-line blocks
    block-spacing: "error"

    # enforce consistent brace style for blocks
    brace-style: "error"

    # enforce camelcase naming convention
    camelcase: "error"

    # enforce or disallow capitalization of the first letter of a comment
    # capitalized-comments: "off"

    # require or disallow trailing commas
    comma-dangle: ["error", "never"]

    # enforce consistent spacing before and after commas
    comma-spacing: "error"

    # enforce consistent comma style
    comma-style: "error"

    # enforce consistent spacing inside computed property brackets
    computed-property-spacing: "error"

    # enforce consistent naming when capturing the current execution context
    # consistent-this: "off"

    # enforce at least one newline at the end of files
    eol-last: "error"

    # require or disallow spacing between function identifiers and their invocations
    func-call-spacing: "error"

    # require function names to match the name of the variable or property to which they are assigned
    # func-name-matching: "off"

    # enforce named function expressions
    func-names: "off" # recommended by Airbnb

    # enforce the consistent use of either function declarations or expressions
    # func-style: "off"

    # disallow specified identifiers
    # id-blacklist: "off"

    # enforce minimum and maximum identifier lengths
    # id-length: "off"

    # require identifiers to match a specified regular expression
    # id-match: "off"

    # enforce consistent indentation
    indent: ["error", 4]

    # enforce the consistent use of either double or single quotes in JSX attributes
    # jsx-quotes: "off"

    # enforce consistent spacing between keys and values in object literal properties
    key-spacing: "error"

    # enforce consistent spacing before and after keywords
    keyword-spacing: "error"

    # enforce position of line comments
    # line-comment-position: "off"

    # enforce consistent linebreak style
    # linebreak-style: "off"

    # require empty lines around comments
    # lines-around-comment: "off"

    # require or disallow newlines around directives
    # lines-around-directive: "off"

    # enforce a maximum depth that blocks can be nested
    # max-depth: "off"

    # enforce a maximum line length
    max-len: ["error", 125]

    # enforce a maximum file length
    # max-lines: "off"

    # enforce a maximum depth that callbacks can be nested
    # max-nested-callbacks: "off"

    # enforce a maximum number of parameters in function definitions
    # max-params: "off"

    # enforce a maximum number of statements allowed per line
    max-statements-per-line: "error"

    # enforce a maximum number of statements allowed in function blocks
    # max-statements: "off"

    # enforce newlines between operands of ternary expressions
    # multiline-ternary: "off"

    # require constructor function names to begin with a capital letter
    new-cap: "error"

    # require parentheses when invoking a constructor with no arguments
    new-parens: "error"

    # require or disallow an empty line after var declarations
    # newline-after-var: "off"

    # require an empty line before return statements
    # newline-before-return: "off"

    # require a newline after each call in a method chain
    newline-per-chained-call: "off" # recommended by Airbnb

    # disallow Array constructors
    no-array-constructor: "error"

    # disallow bitwise operators
    # no-bitwise: "off"

    # disallow continue statements
    # no-continue: "off"

    # disallow inline comments after code
    # no-inline-comments: "off"

    # disallow if statements as the only statement in else blocks
    no-lonely-if: "error"

    # disallow mixes of different operators
    # no-mixed-operators: "off"

    # disallow mixed spaces and tabs for indentation
    # no-mixed-spaces-and-tabs: "off"

    # disallow multiple empty lines
    no-multiple-empty-lines: ["error", { "max": 1, "maxBOF": 0, "maxEOF": 1}]

    # disallow negated conditions
    no-negated-condition: "error"

    # disallow nested ternary expressions
    no-nested-ternary: "error"

    # disallow Object constructors
    no-new-object: "error"

    # disallow the unary operators ++ and --
    # no-plusplus: "off"

    # disallow specified syntax
    no-restricted-syntax: "off" # recommended by Airbnb

    # Disallow tabs in file
    no-tabs: "error"

    # disallow ternary operators
    # no-ternary: "off"

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

    # disallow dangling underscores in identifiers
    no-underscore-dangle: "error"

    # disallow ternary operators when simpler alternatives exist
    no-unneeded-ternary: ["error", { "defaultAssignment": false }]

    # disallow whitespace before properties
    no-whitespace-before-property: "error"

    # enforce consistent line breaks inside braces
    # object-curly-newline: "off"

    # enforce consistent spacing inside braces
    object-curly-spacing: ["error", "always"]

    # enforce placing object properties on separate lines
    object-property-newline: "error"

    # require or disallow newlines around var declarations
    # one-var-declaration-per-line: "off"

    # enforce variables to be declared either together or separately in functions
    one-var: ["error", "never"]

    # require or disallow assignment operator shorthand where possible
    # operator-assignment: "off"

    # enforce consistent linebreak style for operators
    operator-linebreak: ["error", "before", { "overrides": { "=": "after" } }]

    # require or disallow padding within blocks
    padded-blocks: "off" # recommended by Airbnb and Google

    # require quotes around object literal property names
    quote-props: ["error", "consistent-as-needed"]

    # enforce the consistent use of either backticks, double, or single quotes
    quotes: ["error", "single", { "avoidEscape": true }]

    # require JSDoc comments
    require-jsdoc: "off" # recommended by Google

    # enforce consistent spacing before and after semicolons
    semi-spacing: "error"

    # require or disallow semicolons instead of ASI
    semi: "error"

    # requires object keys to be sorted
    # sort-keys: "off"

    # require variables within the same declaration block to be sorted
    # sort-vars: "off"

    # enforce consistent spacing before blocks
    space-before-blocks: "error"

    # enforce consistent spacing before function definition opening parenthesis
    space-before-function-paren: ["error", "never"]

    # enforce consistent spacing inside parentheses
    space-in-parens: "error"

    # require spacing around operators
    space-infix-ops: "error"

    # enforce consistent spacing before or after unary operators
    space-unary-ops: "error"

    # enforce consistent spacing after the // or /* in a comment
    spaced-comment: ["error", "always"]

    # require or disallow Unicode BOM
    # unicode-bom: "off"

    # require parenthesis around regex literals
    # wrap-regex: "off"