.eslintrc.js

const indentOptions = {
  // Folowing numbers are multiplier of origin indent level (2 spaces in our case)
  SwitchCase: 1, // Enforces indentation level for case clauses in switch statements
  VariableDeclarator: 'first', // Enforces indentation level for variable declarators
  outerIIFEBody: 1, // Enforces indentation level for file-level IIFEs
  MemberExpression: 1, // Enforces indentation level for multi-line property chains
  FunctionDeclaration: {
    parameters: 'first', // Enforces indentation level for parameters in a function declaration
    body: 1, // Enforces indentation level for the body of a function declaration
  },
  FunctionExpression: {
    parameters: 'first', // Enforces indentation level for parameters in a function expression
    body: 1, // Enforces indentation level for the body of a function expression
  },
  CallExpression: {
    arguments: 1, // Enforces indentation level for arguments in a call expression
  },
  ArrayExpression: 1, // Enforces indentation level for elements in arrays
  ObjectExpression: 1, // Enforces indentation level for elements in objects
  ImportDeclaration: 1, // Enforces indentation level for import statements
  flatTernaryExpressions: true, // Equires no indentation for ternary expressions which are nested in other ternary
  ignoreComments: false,
};
const noExtraParensOptions = {
  conditionalAssign: false,
  returnAssign: false,
  nestedBinaryExpressions: true, // No parens around (a && b)
  enforceForArrowConditionals: true, // No parens around arrow return expression a => (a ? b : c)
};
const noUnusedVarsOptions = { 'vars': 'all', 'args': 'after-used', 'ignoreRestSiblings': true };
const noUseBeforeDefineOptions = { functions: false, classes: true };

module.exports = {
  'root': true,

  'env': {
    'amd': true,
    'es6': true,
    'jest': true,
    'node': true,
    'browser': true,
  },

  'parserOptions': {
    'ecmaVersion': 2020,
    'sourceType': 'module',
  },

  'rules': {
    /** ES6 section http://eslint.org/docs/rules/#ecmascript-6 */
    // enforces no braces where they can be omitted
    'arrow-body-style': [2, 'as-needed', { 'requireReturnForObjectLiteral': false }],
    // require parens in arrow function arguments
    'arrow-parens': [2, 'as-needed'],
    // require space before/after arrow function's arrow
    'arrow-spacing': [2, { 'before': true, 'after': true }],
    // require trailing commas in multiline object literals
    'comma-dangle': [2, {
      'arrays': 'always-multiline',
      'objects': 'always-multiline',
      'imports': 'always-multiline',
      'exports': 'always-multiline',
      'functions': 'ignore',
    }],
    // verify super() callings in constructors
    'constructor-super': 0,
    // enforce the spacing around the * in generator functions
    'generator-star-spacing': [2, {
      'before': false,
      'after': true,
      'method': { 'before': true, 'after': true },
    }],
    // disallow modifying variables of class declarations
    'no-class-assign': 2,
    // disallow arrow functions where they could be confused with comparisons
    'no-confusing-arrow': 0,
    // disallow modifying variables that are declared using const
    'no-const-assign': 2,
    // disallow duplicate class members
    'no-dupe-class-members': 2,
    // disallow importing from the same path more than once. Use 'import/no-duplicates' instead of this
    'no-duplicate-imports': 0,
    // disallow symbol constructor
    'no-new-symbol': 2,
    // disallow specific globals
    'no-restricted-globals': 0,
    // disallow specific imports
    'no-restricted-imports': 0,
    // disallow to use this/super before super() calling in constructors.
    'no-this-before-super': 0,
    // Require let or const instead of var
    'no-var': 2,
    // disallow unnecessary computed property keys in object literals
    'no-useless-computed-key': 2,
    // disallow unnecessary constructor
    'no-useless-constructor': 2,
    // disallow renaming import, export, and destructured assignments to the same name
    'no-useless-rename': 2,
    // require method and property shorthand syntax for object literals
    'object-shorthand': [2, 'always', { 'avoidQuotes': true }],
    // suggest using arrow functions as callbacks
    'prefer-arrow-callback': [2, { 'allowNamedFunctions': true }],
    // suggest using of const declaration for variables that are never modified after declared
    // destructuring:all means if some variable within destructuring is modified later(let),
    // even if others never(const), whole destructuring can be defined as let
    'prefer-const': [2, { 'destructuring': 'all', 'ignoreReadBeforeAssign': true }],
    // require destructuring from arrays and/or objects
    'prefer-destructuring': 0,
    // disallow parseInt() in favor of binary, octal, and hexadecimal literals
    'prefer-numeric-literals': 2,
    // Suggest using the spread operator instead of .apply()
    'prefer-spread': 2,
    // suggest using Reflect methods where applicable
    'prefer-reflect': 0,
    // use rest parameters instead of arguments
    'prefer-rest-params': 2,
    // suggest using template literals instead of string concatenation
    'prefer-template': 0,
    // disallow generator functions that do not have yield
    'require-yield': 0,
    // import sorting
    'sort-imports': 0,
    // require symbol descriptions
    'symbol-description': 2,
    // enforce usage of spacing in template strings
    'template-curly-spacing': 2,
    // enforce spacing around the * in yield* expressions
    'yield-star-spacing': [2, 'after'],


    /** Best Practices section http://eslint.org/docs/rules/#best-practices **/
    // enforces getter/setter pairs in objects
    'accessor-pairs': 0,
    // enforces return statements in callbacks of array's methods
    'array-callback-return': 0,
    // treat var statements as if they were block scoped
    'block-scoped-var': 0,
    // enforce that class methods utilize this
    'class-methods-use-this': 0,
    // specify the maximum cyclomatic complexity allowed in a program
    'complexity': [0, 11],
    // require return statements to either always or never specify values
    'consistent-return': 0,
    // specify curly brace conventions for all control statements
    'curly': [2, 'all'],
    // require default case in switch statements
    'default-case': 0,
    // encourages use of dot notation whenever possible
    'dot-notation': 2,
    // 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,
    // enforce a maximum number of classes per file
    'max-classes-per-file': 0,
    // Blacklist certain identifiers to prevent them being used
    'id-blacklist': 0,
    // 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/default clauses
    'no-case-declarations': 0,
    // 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, { 'allowElseIf': false }],
    // disallow empty functions
    'no-empty-function': [2, { allow: ['arrowFunctions'] }],
    // disallow Unnecessary Labels
    'no-extra-label': 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': 0,
    // disallow the use of leading or trailing decimal points in numeric literals
    'no-floating-decimal': 2,
    // disallow assignments to native objects or read-only global variables
    'no-global-assign': 2,
    // disallow the type conversions with shorter notations
    'no-implicit-coercion': 0,
    // 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 labels for anything other then loops and switches
    'no-labels': [2, { 'allowLoop': true, 'allowSwitch': false }],
    // disallow unnecessary nested blocks
    'no-lone-blocks': 0,
    // disallow magic numbers
    'no-magic-numbers': 0,
    // disallow creation of functions within loops
    'no-loop-func': 0,
    // disallow use of multiple spaces
    'no-multi-spaces': [2, {'ignoreEOLComments': true}],
    // disallow use of multiline strings
    'no-multi-str': 2,
    // disallow use of new operator when not part of the assignment or comparison
    'no-new': 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 (old style) octal literals
    'no-octal': 2,
    // disallow use of octal escape sequences in string literals, such as
    // var foo = 'Copyright \251';
    'no-octal-escape': 2,
    // disallow reassignment of function parameters
    // disallow parameter object manipulation
    'no-param-reassign': 0,
    // disallow use of process.env
    'no-process-env': 0,
    // disallow usage of __proto__ property
    'no-proto': 2,
    // disallow declaring the same variable more then once
    'no-redeclare': [2, { 'builtinGlobals': true }],
    // disallow certain properties on certain objects
    'no-restricted-properties': [0, [
      { 'object': '_', 'property': 'chain' },
    ]],
    // disallow use of assignment in return statement
    'no-return-assign': 0,
    // disallow unnecessary return await
    'no-return-await': 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': 2,
    // disallow unmodified conditions of loops
    // http://eslint.org/docs/rules/no-unmodified-loop-condition
    'no-unmodified-loop-condition': 2,
    // disallow usage of expressions in statement position
    'no-unused-expressions': 2,
    // disallow unused labels
    'no-unused-labels': 2,
    // disallow unnecessary .call() and .apply()
    'no-useless-call': 0,
    // disallow unnecessary catch clauses
    'no-useless-catch': 2,
    // Disallow unnecessary escape usage
    'no-useless-escape': 2,
    // Disallow redundant return statements
    'no-useless-return': 0,
    // disallow use of void operator
    'no-void': 2,
    // disallow usage of configurable warning terms in comments: e.g.
    'no-warning-comments': [0, { 'terms': ['todo', 'fixme', 'xxx'], 'location': 'start' }],
    // disallow use of the with statement
    'no-with': 2,
    // enforce using named capture group in regular expression
    'prefer-named-capture-group': 0,
    // require using Error objects as Promise rejection reasons
    'prefer-promise-reject-errors': 2,
    // require use of the second argument for parseInt()
    'radix': 2,
    // disallow async functions which have no await expression
    'require-await': 0,
    // enforce the use of u flag on RegExp
    'require-unicode-regexp': 0,
    // requires to declare all vars on top of their containing scope
    'vars-on-top': 0,
    // require immediate function invocation to be wrapped in parentheses
    // http://eslint.org/docs/rules/wrap-iife.html
    'wrap-iife': [2, 'outside', { 'functionPrototypeMethods': true }],
    // require or disallow Yoda conditions
    'yoda': 2,


    /** Variables section http://eslint.org/docs/rules/#variables **/
    // enforce or disallow variable initializations at definition
    'init-declarations': 0,
    // disallow deletion of variables
    'no-delete-var': 2,
    // disallow var and named functions in global scope
    'no-implicit-globals': 2,
    // disallow labels that share a name with a variable
    'no-label-var': 2,
    // disallow self assignment
    'no-self-assign': [2, { 'props': true }],
    // disallow shadowing of names such as arguments
    'no-shadow-restricted-names': 2,
    // disallow declaration of variables already declared in the outer scope
    'no-shadow': [0, { 'builtinGlobals': true, 'hoist': 'functions', 'allow': [] }],
    // 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': [2, noUnusedVarsOptions],
    // disallow use of variables before they are defined
    'no-use-before-define': [2, noUseBeforeDefineOptions],


    /** Possible Errors section http://eslint.org/docs/rules/#possible-errors **/
    // enforce “for” loop update clause moving the counter in the right direction.
    'for-direction': 2,
    // enforce return statements in getters
    'getter-return': 2,
    // disallow using an async function as a Promise executor
    'no-async-promise-executor': 2,
    // disallow await inside of loops
    'no-await-in-loop': 0,
    // disallow comparing against -0. Use Object.is(x, -0)
    'no-compare-neg-zero': 2,
    // disallow assignment in conditional expressions
    'no-cond-assign': [2, 'always'],
    // disallow use of console
    'no-console': 0,
    // 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': 0,
    // disallow duplicate arguments in functions
    'no-dupe-args': 2,
    // Creating objects with duplicate keys in objects can cause unexpected behavior in your application
    '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.
    // if you are not sure about operator precedence, visit that page
    // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Operator_Precedence#Table
    'no-extra-parens': [2, 'all', noExtraParensOptions],
    // 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 characters which are made with multiple code points in character class syntax
    'no-misleading-character-class': 0,
    // disallow the use of object properties of the global object (Math and JSON) as functions
    'no-obj-calls': 2,
    // disallow use of Object.prototypes builtins directly
    'no-prototype-builtins': 0,
    // disallow multiple spaces in a regular expression literal
    'no-regex-spaces': 2,
    // disallow sparse arrays
    'no-sparse-arrays': 2,
    // Disallow template literal placeholder syntax in regular strings
    'no-template-curly-in-string': 0,
    // disallow unreachable statements after a return, throw, continue, or break statement
    'no-unreachable': 2,
    // disallow control flow statements in finally blocks
    'no-unsafe-finally': 2,
    // disallow negating the left operand of relational operators
    'no-unsafe-negation': 2,
    // disallow assignments that can lead to race conditions due to usage of await or yield.
    'require-atomic-updates': 0,
    // disallow comparisons with the value NaN
    'use-isnan': 2,
    // ensure JSDoc comments are valid
    'valid-jsdoc': 0,
    // ensure that the results of typeof are compared against a valid string
    'valid-typeof': 2,
    // Avoid code that looks like two expressions but is actually one
    'no-unexpected-multiline': 2,

    /** Stylistic Issues section http://eslint.org/docs/rules/#stylistic-issues **/
    // enforce linebreaks after opening and before closing array brackets
    'array-bracket-newline': [2, 'consistent'],
    // enforce spacing inside array brackets
    'array-bracket-spacing': [2, 'never'],
    // enforce line breaks after each array element
    'array-element-newline': 0,
    // enforce consistent spacing inside single-line blocks
    'block-spacing': [2, 'never'],
    // enforce one true brace style
    'brace-style': [2, '1tbs', { 'allowSingleLine': false }],
    // require camel case names
    'camelcase': [2, { 'properties': 'never', 'ignoreDestructuring': true, allow: [] }],
    // enforce or disallow capitalization of the first letter of a comment
    'capitalized-comments': [0, 'always', {'ignoreInlineComments': true, 'ignoreConsecutiveComments': true}],
    // 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'],
    // 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': 2,
    // require or disallow spacing between function identifiers and their invocations
    'func-call-spacing': 2,
    // require function names to match the name of the variable or property to which they are assigned
    'func-name-matching': [2, 'always', { 'considerPropertyDescriptor': true, 'includeCommonJSModuleExports': false }],
    // require function expressions to have a name
    'func-names': 0,
    // enforces use of function declarations or expressions
    'func-style': 0,
    // enforce line breaks between arguments of a function call
    'function-call-argument-newline': [0, 'consistent'],
    // enforce consistent line breaks inside function parentheses.
    // currently conflicts with max-len and if argument is a function with argument on first line
    'function-paren-newline': [0, 'multiline'],
    // enforces minimum and maximum identifier lengths (variable names, property names etc.)
    'id-length': 0,
    // enforce consistent indentation
    'indent': [2, 2, indentOptions],
    // 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, {
      'before': true,
      'after': true,
      'overrides': {
        'return': { 'after': true },
        'throw': { 'after': true },
        'case': { 'after': true },
      }
    }],
    // enforce position of line comments
    'line-comment-position': 0,
    // disallow mixed 'LF' and 'CRLF' as linebreaks
    'linebreak-style': 0,
    // enforces empty lines around comments
    'lines-around-comment': [2, {
      'beforeBlockComment': true,
      'afterBlockComment': false,
      'beforeLineComment': false,
      'afterLineComment': false,
      'allowBlockStart': true,
      'allowBlockEnd': true,
      'allowClassStart': true,
      'allowClassEnd': true,
      'allowObjectStart': true,
      'allowObjectEnd': true,
      'allowArrayEnd': true,
      'applyDefaultIgnorePatterns': true,
    }],
    // require or disallow an empty line between class members
    'lines-between-class-members': [2, 'always', {'exceptAfterSingleLine': true}],
    // specify the maximum depth that blocks can be nested
    'max-depth': [0, 4],
    // maximum length of a line in your program
    'max-len': [2, {
      'code': 140, // The character count to use whenever a tab character is encountered
      'comments': 140, // Maximum line length for comments; defaults to value of code
      'tabWidth': 2, // The character count to use whenever a tab character is encountered
      'ignoreUrls': true, // Ignores lines that contain a URL
      'ignoreStrings': true, // Ignores lines that contain a double-quoted or single-quoted string
      'ignoreComments': false, // Ignores all trailing comments and comments on their own line
      'ignoreTrailingComments': true, // Ignores only trailing comments
      'ignoreTemplateLiterals': true, // Ignores lines that contain a template literal
      'ignoreRegExpLiterals': true, // Ignores lines that contain a RegExp literal
    }],
    // enforce a maximum file length
    'max-lines': [0, { 'max': 300, 'skipBlankLines': true, 'skipComments': true }],
    // enforce a maximum number of line of code in a function
    'max-lines-per-function': [0, { 'max': 50, 'skipBlankLines': true, 'skipComments': true }],
    // 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],
    // enforce a maximum number of statements allowed per line
    'max-statements-per-lines': 0,
    // enforce a particular style for multiline comments
    'multiline-comment-style': 0,
    // enforce newlines between operands of ternary expressions
    'multiline-ternary': [0, 'always-multiline'],
    // require a capital letter for constructors
    'new-cap': [2, { 'newIsCap': true, 'capIsNew': false }],
    // disallow the omission of parentheses when invoking a constructor with no arguments
    'new-parens': 2,
    // enforces new line after each method call in the chain to make it more readable and easy to maintain
    'newline-per-chained-call': [0, { 'ignoreChainWithDepth': 3 }],
    // disallow use of the Array constructor
    'no-array-constructor': 2,
    // 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': 2,
    // disallow mixed spaces and tabs for indentation
    'no-mixed-spaces-and-tabs': 2,
    // disallow use of chained assignment expressions
    'no-multi-assign': 0,
    // disallow multiple empty lines and only one newline at the end
    'no-multiple-empty-lines': [2, { 'max': 2, 'maxEOF': 1, 'maxBOF': 1 }],
    // disallow nested ternary expressions
    'no-nested-ternary': 0,
    // disallow use of the Object constructor
    'no-new-object': 2,
    // disallow use of unary operators, ++ and --
    'no-plusplus': 0,
    // disallow specified syntax
    'no-restricted-syntax': 0,
    // disallow tabs in file
    'no-tabs': 2,
    // disallow the use of ternary operators
    'no-ternary': 0,
    // disallow trailing whitespace at the end of lines
    'no-trailing-spaces': 2,
    // disallow dangling underscores in identifiers
    'no-underscore-dangle': [2, { 'enforceInMethodNames': false, 'allow': [] }],
    // disallow the use of Boolean literals in conditional expressions
    // also, prefer `a || b` over `a ? a : b`
    'no-unneeded-ternary': [2, { 'defaultAssignment': false }],
    // disallow whitespace before properties
    'no-whitespace-before-property': 2,
    // enforce the location of single-line statements
    'nonblock-statement-body-position': [2, 'beside'],
    // enforce consistent line breaks inside braces
    'object-curly-newline': [2, { 'consistent': true }],
    // Enforce using the eslint-plugin-babel
    'object-curly-spacing': [0, 'never'],
    // enforce placing object properties on separate lines
    'object-property-newline': 0,
    // allow just one var statement per function
    'one-var': [2, 'never'],
    // require a newline around variable declaration
    'one-var-declaration-per-line': [2, 'always'],
    // 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': [2, 'after', {overrides: {'|>': 'before'}}],
    // enforce padding within blocks
    'padded-blocks': [2, {'blocks': 'never', 'classes': 'never', 'switches': 'never'}, {allowSingleLineBlocks: false}],
    // require or disallow padding lines between statements
    'padding-line-between-statements': [2,
      // Always require blank lines after directive (like 'use-strict'), except between directives
      {blankLine: 'always', prev: 'directive', next: '*'},
      {blankLine: 'any',    prev: 'directive', next: 'directive'},
      // Always require blank lines after import, except between imports
      {blankLine: 'always', prev: 'import', next: '*'},
      {blankLine: 'any',    prev: 'import', next: 'import'},
      // Always require blank lines before and after every sequence of variable declarations and export
      {blankLine: 'always', prev: '*', next: ['const', 'let', 'var', 'export']},
      {blankLine: 'always', prev: ['const', 'let', 'var', 'export'], next: '*'},
      {blankLine: 'any',    prev: ['const', 'let', 'var', 'export'], next: ['const', 'let', 'var', 'export']},
      // Always require blank lines before and after class declaration, if, do/while, switch, try, iife
      {blankLine: 'always', prev: '*', next: ['if', 'class', 'for', 'do', 'while', 'switch', 'try', 'iife']},
      {blankLine: 'always', prev: ['if', 'class', 'for', 'do', 'while', 'switch', 'try', 'iife'], next: '*'},
      // Always require blank lines before return statements
      {blankLine: 'always', prev: '*', next: 'return'},
    ],
    // disallow using Object.assign with an object literal as the first argument and prefer the use of object spread instead
    'prefer-object-spread': 2,
    // require quotes around object literal property names
    'quote-props': [2, 'as-needed', { 'keywords': false, 'unnecessary': false, 'numbers': false }],
    // specify whether double or single quotes should be used
    'quotes': [2, 'single', 'avoid-escape'],
    // require identifiers to match the provided regular expression
    'id-match': 0,
    // enforce the location of arrow function bodies
    'implicit-arrow-linebreak': 0,
    // enforce spacing before and after semicolons
    'semi-spacing': [2, { 'before': false, 'after': true }],
    // enforce location of semicolons
    'semi-style': [2, 'last'],
    // require use of semicolons where they are valid instead of ASI
    'semi': [2, 'always', {'omitLastInOneLineBlock': false}],
    // requires object keys to be sorted
    'sort-keys': 0,
    // sort variables within the same declaration block
    'sort-vars': 0,
    // require or disallow space before blocks
    'space-before-blocks': 2,
    // require or disallow space before function opening parenthesis
    'space-before-function-paren': [2, { 'anonymous': 'always', 'named': 'never', 'asyncArrow': 'always' }],
    // require or disallow spaces inside parentheses
    'space-in-parens': [2, 'never'],
    // require spaces around operators
    'space-infix-ops': 2,
    // 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': [0, 'always', {
      'exceptions': ['-', '+'],
      'markers': ['=', '!'],           // space here to support sprockets directives
    }],
    // enforce spacing around colons of switch statements
    'switch-colon-spacing': [2, {'after': true, 'before': false}],
    // require or disallow spacing between template tags and their literals
    'template-tag-spacing': [2, 'never'],
    // files must not begin with the Unicode Byte Order Mark (BOM)
    'unicode-bom': [2, 'never'],
    // require regex literals to be wrapped in parentheses
    'wrap-regex': 0,
  },

  'overrides': [
    {
      'parser': '@typescript-eslint/parser',
      'parserOptions': {
        'tsconfigRootDir': './',
        'project': [
          './tsconfig.eslint.json',
          './packages/*/tsconfig.json',
        ],
        'warnOnUnsupportedTypeScriptVersion': true,
      },

      'plugins': [
        '@typescript-eslint',
      ],

      'files': ['*.ts'],

      'rules': {
        /** Disable ESLint rules, that are handled by the TypeScript */
        // Checked by Typescript - ts(2378)
        'getter-return': 0,
        // Checked by Typescript - ts(2300)
        'no-dupe-args': 0,
        // Checked by Typescript - ts(1117)
        'no-dupe-keys': 0,
        // Checked by Typescript - ts(7027)
        'no-unreachable': 0,
        // Checked by Typescript - ts(2367)
        'valid-typeof': 0,
        // Checked by Typescript - ts(2588)
        'no-const-assign': 0,
        // Checked by Typescript - ts(2588)
        'no-new-symbol': 0,
        // Checked by Typescript - ts(2376)
        'no-this-before-super': 0,
        // This is checked by Typescript using the option `strictNullChecks`.
        'no-undef': 0,
        // This is already checked by Typescript.
        'no-dupe-class-members': 0,
        // This is already checked by Typescript.
        'no-redeclare': 0,

        /** Disable ESLint rules, that are handled by the @typescript-eslint */
        // This is handled by @typescript-eslint/indent
        'indent': 0,
        // This is handled by @typescript-eslint/func-call-spacing
        'func-call-spacing': 0,
        // This is handled by @typescript-eslint/no-array-constructor
        'no-array-constructor': 0,
        // This is handled by @typescript-eslint/no-empty-function
        'no-empty-function': 0,
        // This is handled by @typescript-eslint/no-extra-parens
        'no-extra-parens': 0,
        // This is handled by @typescript-eslint/no-magic-numbers
        'no-magic-numbers': 0,
        // This is handled by @typescript-eslint/no-unused-vars
        'no-unused-vars': 0,
        // This is handled by @typescript-eslint/no-use-before-define
        'no-use-before-define': 0,
        // This is handled by @typescript-eslint/no-useless-constructor
        'no-useless-constructor': 0,
        // This is handled by @typescript-eslint/quotes
        'quotes': 0,
        // This is handled by @typescript-eslint/require-await
        'require-await': 0,
        // This is handled by @typescript-eslint/semi
        'semi': 0,

        /** @typescript-eslint rules */
        // Require that member overloads be consecutive
        '@typescript-eslint/adjacent-overload-signatures': 2,
        // Requires using either T[] or Array<T> for arrays
        '@typescript-eslint/array-type': [2, { default: 'array', readonly: 'array' }],
        // Disallows awaiting a value that is not a Thenable
        '@typescript-eslint/await-thenable': 0,
        // Bans “// @ts-ignore” comments from being used
        '@typescript-eslint/ban-ts-ignore': 0,
        // Bans specific types from being used
        '@typescript-eslint/ban-types': [2, {
          'types': {
            'Array': null,
            'Object': 'Use {} instead',
            'String': {
              'message': 'Use string instead',
              'fixWith': 'string'
            }
          }
        }],
        // Enforce camelCase naming convention
        '@typescript-eslint/camelcase': [2, { properties: 'never', ignoreDestructuring: true, allow: [] }],
        // Require PascalCased class and interface names
        '@typescript-eslint/class-name-casing': [2, { allowUnderscorePrefix: false }],
        // Enforces consistent usage of type assertions
        '@typescript-eslint/consistent-type-assertions': [2, { assertionStyle: 'as', objectLiteralTypeAssertions: 'allow' }],
        // Consistent with type definition either interface or type
        '@typescript-eslint/consistent-type-definitions': [2, 'interface'],
        // Require explicit return types on functions and class methods
        '@typescript-eslint/explicit-function-return-type': [2, {
          // if true, only functions which are part of a declaration will be checked
          allowExpressions: false,
          // if true, type annotations are also allowed on the variable of a function expression rather than on the function directly
          allowTypedFunctionExpressions: true,
          // if true, functions immediately returning another function expression will not be checked
          allowHigherOrderFunctions: true,
        }],
        // Require explicit accessibility modifiers on class properties and methods
        '@typescript-eslint/explicit-member-accessibility': [2, {
          accessibility: 'no-public',
          overrides: {}
        }],
        // Require or disallow spacing between function identifiers and their invocations
        '@typescript-eslint/func-call-spacing': 2,
        // Enforces naming conventions for class members by visibility
        '@typescript-eslint/generic-type-naming': 0,
        // Enforce consistent indentation
        '@typescript-eslint/indent': [2, 2, indentOptions],
        // Require that interface names should or should not prefixed with I
        '@typescript-eslint/interface-name-prefix': [2, { prefixWithI: 'never' }],
        // Require a specific member delimiter style for interfaces and type literals
        '@typescript-eslint/member-delimiter-style': [2, {
          multiline: { delimiter: 'semi', requireLast: true },
          singleline: { delimiter: 'semi', requireLast: false },
        }],
        // Enforces naming conventions for class members by visibility
        '@typescript-eslint/member-naming': 0,
        // Require a consistent member declaration order
        '@typescript-eslint/member-ordering': 0,
        // Disallow generic Array constructors
        '@typescript-eslint/no-array-constructor': 2,
        // Disallow empty functions
        '@typescript-eslint/no-empty-function': [2, { allow: ['arrowFunctions'] }],
        // Disallow the declaration of empty interfaces
        '@typescript-eslint/no-empty-interface': [2, { allowSingleExtends: false }],
        // Disallow usage of the any type
        '@typescript-eslint/no-explicit-any': [2, { fixToUnknown: false, ignoreRestArgs: false }],
        // Disallow unnecessary parentheses
        '@typescript-eslint/no-extra-parens': [2, 'all', noExtraParensOptions],
        // Forbids the use of classes as namespaces
        '@typescript-eslint/no-extraneous-class': [2, {
          allowEmpty: false,
          allowStaticOnly: true,
          allowConstructorOnly: true,
        }],
        // Requires Promise-like values to be handled appropriately
        '@typescript-eslint/no-floating-promises': 2,
        // Disallow iterating over an array with a for-in loop
        '@typescript-eslint/no-for-in-array': 2,
        // Disallows explicit type declarations for variables or parameters initialized to a number, string, or boolean
        '@typescript-eslint/no-inferrable-types': [2, {
          ignoreParameters: false,
          ignoreProperties: false,
        }],
        // Disallows magic numbers
        '@typescript-eslint/no-magic-numbers': 0,
        // Enforce valid definition of new and constructor
        '@typescript-eslint/no-misused-new': 2,
        // Avoid using promises in places not designed to handle them
        '@typescript-eslint/no-misused-promises': [2, { checksVoidReturn: false, checksConditionals: true }],
        // Disallow the use of custom TypeScript modules and namespaces
        '@typescript-eslint/no-namespace': 2,
        // Disallows non-null assertions using the ! postfix operator (Replaced by the optional chaining?)
        '@typescript-eslint/no-non-null-assertion': 0,
        // Disallow the use of parameter properties in class constructors
        '@typescript-eslint/no-parameter-properties': 0,
        // Disallows invocation of require()
        '@typescript-eslint/no-require-imports': 2,
        // Disallow aliasing this
        '@typescript-eslint/no-this-alias': [2, { allowDestructuring: true }],
        // Disallow the use of type aliases
        '@typescript-eslint/no-type-alias': 0,
        // Warns when a namespace qualifier is unnecessary
        '@typescript-eslint/no-unnecessary-qualifier': 2,
        // Warns if an explicitly specified type argument is the default for that type parameter
        '@typescript-eslint/no-unnecessary-type-arguments': 2,
        // Warns if a type assertion does not change the type of an expression
        '@typescript-eslint/no-unnecessary-type-assertion': 2,
        // Disallow unused variables
        '@typescript-eslint/no-unused-vars': [2, noUnusedVarsOptions],
        // Disallow the use of variables before they are defined
        '@typescript-eslint/no-use-before-define': [2, noUseBeforeDefineOptions],
        // Disallow unnecessary constructors
        '@typescript-eslint/no-useless-constructor': 2,
        // Disallows the use of require statements except in import statements
        '@typescript-eslint/no-var-requires': 2,
        // Prefer a ‘for-of’ loop over a standard ‘for’ loop if the index is only used to access the array being iterated
        '@typescript-eslint/prefer-for-of': 2,
        // Use function types instead of interfaces with call signatures
        '@typescript-eslint/prefer-function-type': 2,
        // Enforce includes method over indexOf method
        // Disable as long as we support IE without polyfilling
        '@typescript-eslint/prefer-includes': 0,
        // Require the use of the namespace keyword instead of the module keyword to declare custom TypeScript modules
        '@typescript-eslint/prefer-namespace-keyword': 0,
        // Requires that private members are marked as readonly if they're never modified outside of the constructor
        '@typescript-eslint/prefer-readonly': 2,
        // Prefer RegExp#exec() over String#match() if no global flag is provided
        '@typescript-eslint/prefer-regexp-exec': 2,
        // Enforce the use of String#startsWith and String#endsWith instead of other equivalent methods of checking substrings
        // Disable as long as we use indexOf === 0 for performance reasons
        '@typescript-eslint/prefer-string-starts-ends-with': 0,
        // Requires any function or method that returns a Promise to be marked async
        '@typescript-eslint/promise-function-async': 0,
        // Enforce the consistent use of either backticks, double, or single quotes
        '@typescript-eslint/quotes': [0, 'single', 'avoid-escape'],
        // Enforce giving compare argument to Array#sort
        '@typescript-eslint/require-array-sort-compare': 2,
        // Disallow async functions which have no await expression
        '@typescript-eslint/require-await': 0,
        // When adding two variables, operands must both be of type number or of type string
        '@typescript-eslint/restrict-plus-operands': 2,
        // Require or disallow semicolons instead of ASI
        '@typescript-eslint/semi': [2, 'always', { omitLastInOneLineBlock: false }],
        // Restricts the types allowed in boolean expressions
        '@typescript-eslint/strict-boolean-expressions': [2, { ignoreRhs: true }],
        // Sets preference level for triple slash directives versus ES6-style import declarations
        '@typescript-eslint/triple-slash-reference': [2, { path: 'never', types: 'prefer-import', lib: 'never' }],
        // Require consistent spacing around type annotations
        '@typescript-eslint/type-annotation-spacing': [2, { before: false, after: true }],
        // Requires type annotations to exist
        '@typescript-eslint/typedef': 0,
        // Enforces unbound methods are called with their expected scope
        '@typescript-eslint/unbound-method': [2, { ignoreStatic: true }],
        // Warns for any two overloads that could be unified into one by using a union or an optional/rest parameter
        '@typescript-eslint/unified-signatures': 2,
      }
    }
  ],
};