/** * ESLint Configuration - Airbnb Style Guide * * This configuration file contains all the rules and best practices from the * Airbnb JavaScript Style Guide, converted to the modern ESLint flat config format. * * The rules are organized into the following categories: * - Possible Errors: Rules to catch potential runtime errors and logic issues * - Best Practices: Rules to enforce JavaScript best practices * - Strict Mode: Enforces proper use of strict mode * - Variables: Rules for variable declarations and scoping * - Node.js and CommonJS: Node.js specific rules * - Stylistic Issues: Code formatting and style rules * - ECMAScript 6: Modern ES6+ syntax rules * * Key style conventions: * - Single quotes for strings (with escape allowance) * - 2-space indentation * - Semicolons required * - Use const/let instead of var * - Arrow functions preferred for callbacks * - Template literals preferred over concatenation * - Trailing commas in multiline structures * - Max line length of 100 characters * - Strict equality (===) required * * @see https://github.com/airbnb/javascript */ import js from '@eslint/js'; import globals from 'globals'; export default [ js.configs.recommended, { files: ['**/*.js'], languageOptions: { ecmaVersion: 'latest', sourceType: 'module', globals: { ...globals.node, ...globals.es2021, }, }, rules: { // Possible Errors 'for-direction': 'error', 'getter-return': ['error', { allowImplicit: true }], 'no-async-promise-executor': 'error', 'no-await-in-loop': 'error', 'no-compare-neg-zero': 'error', 'no-cond-assign': ['error', 'always'], 'no-console': 'warn', 'no-constant-condition': 'warn', 'no-control-regex': 'error', 'no-debugger': 'error', 'no-dupe-args': 'error', 'no-dupe-else-if': 'error', 'no-dupe-keys': 'error', 'no-duplicate-case': 'error', 'no-empty': 'error', 'no-empty-character-class': 'error', 'no-ex-assign': 'error', 'no-extra-boolean-cast': 'error', 'no-extra-parens': ['off', 'all', { conditionalAssign: true, nestedBinaryExpressions: false, returnAssign: false, ignoreJSX: 'all', enforceForArrowConditionals: false, }], 'no-extra-semi': 'error', 'no-func-assign': 'error', 'no-import-assign': 'error', 'no-inner-declarations': 'error', 'no-invalid-regexp': 'error', 'no-irregular-whitespace': 'error', 'no-loss-of-precision': 'error', 'no-misleading-character-class': 'error', 'no-obj-calls': 'error', 'no-promise-executor-return': 'error', 'no-prototype-builtins': 'error', 'no-regex-spaces': 'error', 'no-setter-return': 'error', 'no-sparse-arrays': 'error', 'no-template-curly-in-string': 'error', 'no-unexpected-multiline': 'error', 'no-unreachable': 'error', 'no-unreachable-loop': ['error', { ignore: [] }], 'no-unsafe-finally': 'error', 'no-unsafe-negation': 'error', 'no-unsafe-optional-chaining': ['error', { disallowArithmeticOperators: true }], 'no-useless-backreference': 'error', 'use-isnan': 'error', 'valid-typeof': ['error', { requireStringLiterals: true }], // Best Practices 'accessor-pairs': 'off', 'array-callback-return': ['error', { allowImplicit: true }], 'block-scoped-var': 'error', complexity: ['off', 20], 'class-methods-use-this': ['error', { exceptMethods: [] }], 'consistent-return': 'error', curly: ['error', 'multi-line'], 'default-case': ['error', { commentPattern: '^no default$' }], 'default-case-last': 'error', 'default-param-last': 'error', 'dot-notation': ['error', { allowKeywords: true }], 'dot-location': ['error', 'property'], eqeqeq: ['error', 'always', { null: 'ignore' }], 'grouped-accessor-pairs': 'error', 'guard-for-in': 'error', 'max-classes-per-file': ['error', 1], 'no-alert': 'warn', 'no-caller': 'error', 'no-case-declarations': 'error', 'no-constructor-return': 'error', 'no-div-regex': 'off', 'no-else-return': ['error', { allowElseIf: false }], 'no-empty-function': ['error', { allow: ['arrowFunctions', 'functions', 'methods'], }], 'no-empty-pattern': 'error', 'no-eq-null': 'off', 'no-eval': 'error', 'no-extend-native': 'error', 'no-extra-bind': 'error', 'no-extra-label': 'error', 'no-fallthrough': 'error', 'no-floating-decimal': 'error', 'no-global-assign': ['error', { exceptions: [] }], 'no-implicit-coercion': ['off', { boolean: false, number: true, string: true, allow: [], }], 'no-implicit-globals': 'off', 'no-implied-eval': 'error', 'no-invalid-this': 'off', 'no-iterator': 'error', 'no-labels': ['error', { allowLoop: false, allowSwitch: false }], 'no-lone-blocks': 'error', 'no-loop-func': 'error', 'no-magic-numbers': ['off', { ignore: [], ignoreArrayIndexes: true, enforceConst: true, detectObjects: false, }], 'no-multi-spaces': ['error', { ignoreEOLComments: false }], 'no-multi-str': 'error', 'no-new': 'error', 'no-new-func': 'error', 'no-new-wrappers': 'error', 'no-nonoctal-decimal-escape': 'error', 'no-octal': 'error', 'no-octal-escape': 'error', 'no-param-reassign': ['error', { props: true, ignorePropertyModificationsFor: [ 'acc', 'accumulator', 'e', 'ctx', 'context', 'req', 'request', 'res', 'response', '$scope', 'staticContext', ], }], 'no-proto': 'error', 'no-redeclare': 'error', 'no-restricted-properties': ['error', { object: 'arguments', property: 'callee', message: 'arguments.callee is deprecated', }, { object: 'global', property: 'isFinite', message: 'Please use Number.isFinite instead', }, { object: 'self', property: 'isFinite', message: 'Please use Number.isFinite instead', }, { object: 'window', property: 'isFinite', message: 'Please use Number.isFinite instead', }, { object: 'global', property: 'isNaN', message: 'Please use Number.isNaN instead', }, { object: 'self', property: 'isNaN', message: 'Please use Number.isNaN instead', }, { object: 'window', property: 'isNaN', message: 'Please use Number.isNaN instead', }, { property: '__defineGetter__', message: 'Please use Object.defineProperty instead.', }, { property: '__defineSetter__', message: 'Please use Object.defineProperty instead.', }, { object: 'Math', property: 'pow', message: 'Use the exponentiation operator (**) instead.', }], 'no-return-assign': ['error', 'always'], 'no-return-await': 'error', 'no-script-url': 'error', 'no-self-assign': ['error', { props: true }], 'no-self-compare': 'error', 'no-sequences': 'error', 'no-throw-literal': 'error', 'no-unmodified-loop-condition': 'off', 'no-unused-expressions': ['error', { allowShortCircuit: false, allowTernary: false, allowTaggedTemplates: false, }], 'no-unused-labels': 'error', 'no-useless-call': 'off', 'no-useless-catch': 'error', 'no-useless-concat': 'error', 'no-useless-escape': 'error', 'no-useless-return': 'error', 'no-void': 'error', 'no-warning-comments': ['off', { terms: ['todo', 'fixme', 'xxx'], location: 'start' }], 'no-with': 'error', 'prefer-promise-reject-errors': ['error', { allowEmptyReject: true }], 'prefer-named-capture-group': 'off', 'prefer-regex-literals': ['error', { disallowRedundantWrapping: true }], radix: 'error', 'require-await': 'off', 'require-unicode-regexp': 'off', 'vars-on-top': 'error', 'wrap-iife': ['error', 'outside', { functionPrototypeMethods: false }], yoda: 'error', // Strict Mode strict: ['error', 'never'], // Variables 'init-declarations': 'off', 'no-delete-var': 'error', 'no-label-var': 'error', 'no-restricted-globals': ['error', { name: 'isFinite', message: 'Use Number.isFinite instead' }, { name: 'isNaN', message: 'Use Number.isNaN instead' }, ], 'no-shadow': 'error', 'no-shadow-restricted-names': 'error', 'no-undef': 'error', 'no-undef-init': 'error', 'no-undefined': 'off', 'no-unused-vars': ['error', { vars: 'all', args: 'after-used', ignoreRestSiblings: true }], 'no-use-before-define': ['error', { functions: true, classes: true, variables: true }], // Node.js and CommonJS 'callback-return': 'off', 'global-require': 'error', 'handle-callback-err': 'off', 'no-buffer-constructor': 'error', 'no-mixed-requires': ['off', false], 'no-new-require': 'error', 'no-path-concat': 'error', 'no-process-env': 'off', 'no-process-exit': 'off', 'no-restricted-modules': 'off', 'no-sync': 'off', // Stylistic Issues 'array-bracket-newline': ['off', 'consistent'], 'array-element-newline': ['off', { multiline: true, minItems: 3 }], 'array-bracket-spacing': ['error', 'never'], 'block-spacing': ['error', 'always'], 'brace-style': ['error', '1tbs', { allowSingleLine: true }], camelcase: ['error', { properties: 'never', ignoreDestructuring: false }], 'capitalized-comments': ['off', 'never', { line: { ignorePattern: '.*', ignoreInlineComments: true, ignoreConsecutiveComments: true, }, block: { ignorePattern: '.*', ignoreInlineComments: true, ignoreConsecutiveComments: true, }, }], 'comma-dangle': ['error', { arrays: 'always-multiline', objects: 'always-multiline', imports: 'always-multiline', exports: 'always-multiline', functions: 'always-multiline', }], 'comma-spacing': ['error', { before: false, after: true }], '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, }, }], 'computed-property-spacing': ['error', 'never'], 'consistent-this': 'off', 'eol-last': ['error', 'always'], 'function-call-argument-newline': ['error', 'consistent'], 'func-call-spacing': ['error', 'never'], 'func-name-matching': ['off', 'always', { includeCommonJSModuleExports: false, considerPropertyDescriptor: true, }], 'func-names': 'warn', 'func-style': ['off', 'expression'], 'function-paren-newline': ['error', 'multiline-arguments'], 'id-denylist': 'off', 'id-length': 'off', 'id-match': 'off', 'implicit-arrow-linebreak': ['error', 'beside'], indent: ['error', 2, { SwitchCase: 1, VariableDeclarator: 1, outerIIFEBody: 1, FunctionDeclaration: { parameters: 1, body: 1, }, FunctionExpression: { parameters: 1, body: 1, }, CallExpression: { arguments: 1, }, ArrayExpression: 1, ObjectExpression: 1, ImportDeclaration: 1, flatTernaryExpressions: false, ignoredNodes: ['JSXElement', 'JSXElement > *', 'JSXAttribute', 'JSXIdentifier', 'JSXNamespacedName', 'JSXMemberExpression', 'JSXSpreadAttribute', 'JSXExpressionContainer', 'JSXOpeningElement', 'JSXClosingElement', 'JSXFragment', 'JSXOpeningFragment', 'JSXClosingFragment', 'JSXText', 'JSXEmptyExpression', 'JSXSpreadChild'], ignoreComments: false, }], 'jsx-quotes': ['off', 'prefer-double'], 'key-spacing': ['error', { beforeColon: false, afterColon: true }], 'keyword-spacing': ['error', { before: true, after: true, overrides: { return: { after: true }, throw: { after: true }, case: { after: true }, }, }], 'line-comment-position': ['off', { position: 'above', ignorePattern: '', applyDefaultPatterns: true, }], 'linebreak-style': ['error', 'unix'], 'lines-between-class-members': ['error', 'always', { exceptAfterSingleLine: false }], 'lines-around-comment': 'off', 'lines-around-directive': ['error', { before: 'always', after: 'always', }], 'max-depth': ['off', 4], 'max-len': ['error', 100, 2, { ignoreUrls: true, ignoreComments: false, ignoreRegExpLiterals: true, ignoreStrings: true, ignoreTemplateLiterals: true, }], 'max-lines': ['off', { max: 300, skipBlankLines: true, skipComments: true, }], 'max-lines-per-function': ['off', { max: 50, skipBlankLines: true, skipComments: true, IIFEs: true, }], 'max-nested-callbacks': 'off', 'max-params': ['off', 3], 'max-statements': ['off', 10], 'max-statements-per-line': ['off', { max: 1 }], 'multiline-comment-style': ['off', 'starred-block'], 'multiline-ternary': ['off', 'never'], 'new-cap': ['error', { newIsCap: true, newIsCapExceptions: [], capIsNew: false, capIsNewExceptions: ['Immutable.Map', 'Immutable.Set', 'Immutable.List'], }], 'new-parens': 'error', 'newline-after-var': 'off', 'newline-before-return': 'off', 'newline-per-chained-call': ['error', { ignoreChainWithDepth: 4 }], 'no-array-constructor': 'error', 'no-bitwise': 'error', 'no-continue': 'error', 'no-inline-comments': 'off', 'no-lonely-if': 'error', 'no-mixed-operators': ['error', { groups: [ ['%', '**'], ['%', '+'], ['%', '-'], ['%', '*'], ['%', '/'], ['/', '*'], ['&', '|', '<<', '>>', '>>>'], ['==', '!=', '===', '!=='], ['&&', '||'], ], allowSamePrecedence: false, }], 'no-mixed-spaces-and-tabs': 'error', 'no-multi-assign': ['error'], 'no-multiple-empty-lines': ['error', { max: 1, maxBOF: 0, maxEOF: 0 }], 'no-negated-condition': 'off', 'no-nested-ternary': 'error', 'no-new-object': 'error', 'no-plusplus': 'error', '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.', }, ], 'no-tabs': 'error', 'no-ternary': 'off', 'no-trailing-spaces': ['error', { skipBlankLines: false, ignoreComments: false, }], 'no-underscore-dangle': ['error', { allow: [], allowAfterThis: false, allowAfterSuper: false, enforceInMethodNames: true, }], 'no-unneeded-ternary': ['error', { defaultAssignment: false }], 'no-whitespace-before-property': 'error', 'nonblock-statement-body-position': ['error', 'beside', { overrides: {} }], 'object-curly-spacing': ['error', 'always'], '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 }, }], 'object-property-newline': ['error', { allowAllPropertiesOnSameLine: true, }], 'one-var': ['error', 'never'], 'one-var-declaration-per-line': ['error', 'always'], 'operator-assignment': ['error', 'always'], 'operator-linebreak': ['error', 'before', { overrides: { '=': 'none' } }], 'padded-blocks': ['error', { blocks: 'never', classes: 'never', switches: 'never', }, { allowSingleLineBlocks: true, }], 'padding-line-between-statements': 'off', 'prefer-exponentiation-operator': 'error', 'prefer-object-spread': 'error', 'quote-props': ['error', 'as-needed', { keywords: false, unnecessary: true, numbers: false }], quotes: ['error', 'single', { avoidEscape: true }], 'require-jsdoc': 'off', semi: ['error', 'always'], 'semi-spacing': ['error', { before: false, after: true }], 'semi-style': ['error', 'last'], 'sort-keys': ['off', 'asc', { caseSensitive: false, natural: true }], 'sort-vars': 'off', 'space-before-blocks': 'error', 'space-before-function-paren': ['error', { anonymous: 'always', named: 'never', asyncArrow: 'always', }], 'space-in-parens': ['error', 'never'], 'space-infix-ops': 'error', 'space-unary-ops': ['error', { words: true, nonwords: false, overrides: {}, }], 'spaced-comment': ['error', 'always', { line: { exceptions: ['-', '+'], markers: ['=', '!', '/'], }, block: { exceptions: ['-', '+'], markers: ['=', '!', ':', '::'], balanced: true, }, }], 'switch-colon-spacing': ['error', { after: true, before: false }], 'template-tag-spacing': ['error', 'never'], 'unicode-bom': ['error', 'never'], 'wrap-regex': 'off', // ECMAScript 6 'arrow-body-style': ['error', 'as-needed', { requireReturnForObjectLiteral: false, }], 'arrow-parens': ['error', 'always'], 'arrow-spacing': ['error', { before: true, after: true }], 'constructor-super': 'error', 'generator-star-spacing': ['error', { before: false, after: true }], 'no-class-assign': 'error', 'no-confusing-arrow': ['error', { allowParens: true }], 'no-const-assign': 'error', 'no-dupe-class-members': 'error', 'no-duplicate-imports': 'off', 'no-new-symbol': 'error', 'no-restricted-exports': ['error', { restrictedNamedExports: ['default', 'then'], }], 'no-restricted-imports': ['off', { paths: [], patterns: [], }], 'no-this-before-super': 'error', 'no-useless-computed-key': 'error', 'no-useless-constructor': 'error', 'no-useless-rename': ['error', { ignoreDestructuring: false, ignoreImport: false, ignoreExport: false, }], 'no-var': 'error', 'object-shorthand': ['error', 'always', { ignoreConstructors: false, avoidQuotes: true, }], 'prefer-arrow-callback': ['error', { allowNamedFunctions: false, allowUnboundThis: true, }], 'prefer-const': ['error', { destructuring: 'any', ignoreReadBeforeAssign: true, }], 'prefer-destructuring': ['error', { VariableDeclarator: { array: false, object: true, }, AssignmentExpression: { array: true, object: false, }, }, { enforceForRenamedProperties: false, }], 'prefer-numeric-literals': 'error', 'prefer-reflect': 'off', 'prefer-rest-params': 'error', 'prefer-spread': 'error', 'prefer-template': 'error', 'require-yield': 'error', 'rest-spread-spacing': ['error', 'never'], 'sort-imports': ['off', { ignoreCase: false, ignoreDeclarationSort: false, ignoreMemberSort: false, memberSyntaxSortOrder: ['none', 'all', 'multiple', 'single'], }], 'symbol-description': 'error', 'template-curly-spacing': 'error', 'yield-star-spacing': ['error', 'after'], }, }, ];