Overview

@typescript-eslint/eslint-plugin includes over 100 rules that detect best practice violations, bugs, and/or stylistic issues specifically for TypeScript code. See Configs for how to enable recommended rules using configs.

Supported Rules

Config Group

Metadata

Rule	Config	Fixer	Typed
@typescript-eslint/adjacent-overload-signatures Require that function overload signatures be consecutive	🎨
@typescript-eslint/array-type Require consistently using either T[] or Array<T> for arrays	🎨	🔧
@typescript-eslint/await-thenable Disallow awaiting a value that is not a Thenable	✅		💭
@typescript-eslint/ban-ts-comment Disallow @ts-<directive> comments or require descriptions after directives	✅
@typescript-eslint/ban-tslint-comment Disallow // tslint:<rule-flag> comments	🎨	🔧
@typescript-eslint/ban-types Disallow certain types	✅	🔧 💡
@typescript-eslint/class-literal-property-style Enforce that literals on classes are exposed in a consistent style	🎨	💡
@typescript-eslint/consistent-generic-constructors Enforce specifying generic type arguments on type annotation or constructor name of a constructor call	🎨	🔧
@typescript-eslint/consistent-indexed-object-style Require or disallow the Record type	🎨	🔧
@typescript-eslint/consistent-type-assertions Enforce consistent usage of type assertions	🎨	🔧 💡
@typescript-eslint/consistent-type-definitions Enforce type definitions to consistently use either interface or type	🎨	🔧
@typescript-eslint/consistent-type-exports Enforce consistent usage of type exports		🔧	💭
@typescript-eslint/consistent-type-imports Enforce consistent usage of type imports		🔧
@typescript-eslint/explicit-function-return-type Require explicit return types on functions and class methods
@typescript-eslint/explicit-member-accessibility Require explicit accessibility modifiers on class properties and methods		🔧 💡
@typescript-eslint/explicit-module-boundary-types Require explicit return and argument types on exported functions' and classes' public class methods
@typescript-eslint/member-delimiter-style Require a specific member delimiter style for interfaces and type literals		🔧
@typescript-eslint/member-ordering Require a consistent member declaration order
@typescript-eslint/method-signature-style Enforce using a particular method signature syntax		🔧
@typescript-eslint/naming-convention Enforce naming conventions for everything across a codebase			💭
@typescript-eslint/no-base-to-string Require .toString() to only be called on objects which provide useful information when stringified	✅		💭
@typescript-eslint/no-confusing-non-null-assertion Disallow non-null assertion in locations that may be confusing	🎨	🔧 💡
@typescript-eslint/no-confusing-void-expression Require expressions of type void to appear in statement position	🔒	🔧 💡	💭
@typescript-eslint/no-duplicate-enum-values Disallow duplicate enum member values	✅
@typescript-eslint/no-duplicate-type-constituents Disallow duplicate constituents of union or intersection types	✅	🔧	💭
@typescript-eslint/no-dynamic-delete Disallow using the delete operator on computed key expressions	🔒	🔧
@typescript-eslint/no-empty-interface Disallow the declaration of empty interfaces	🎨	🔧 💡
@typescript-eslint/no-explicit-any Disallow the any type	✅	🔧 💡
@typescript-eslint/no-extra-non-null-assertion Disallow extra non-null assertions	✅	🔧
@typescript-eslint/no-extraneous-class Disallow classes used as namespaces	🔒
@typescript-eslint/no-floating-promises Require Promise-like statements to be handled appropriately	✅	💡	💭
@typescript-eslint/no-for-in-array Disallow iterating over an array with a for-in loop	✅		💭
@typescript-eslint/no-import-type-side-effects Enforce the use of top-level import type qualifier when an import only has specifiers with inline type qualifiers		🔧
@typescript-eslint/no-inferrable-types Disallow explicit type declarations for variables or parameters initialized to a number, string, or boolean	🎨	🔧
@typescript-eslint/no-invalid-void-type Disallow void type outside of generic or return types	🔒
@typescript-eslint/no-meaningless-void-operator Disallow the void operator except when used to discard a value	🔒	🔧 💡	💭
@typescript-eslint/no-misused-new Enforce valid definition of new and constructor	✅
@typescript-eslint/no-misused-promises Disallow Promises in places not designed to handle them	✅		💭
@typescript-eslint/no-mixed-enums Disallow enums from having both number and string members	🔒		💭
@typescript-eslint/no-namespace Disallow TypeScript namespaces	✅
@typescript-eslint/no-non-null-asserted-nullish-coalescing Disallow non-null assertions in the left operand of a nullish coalescing operator	🔒	💡
@typescript-eslint/no-non-null-asserted-optional-chain Disallow non-null assertions after an optional chain expression	✅	💡
@typescript-eslint/no-non-null-assertion Disallow non-null assertions using the ! postfix operator	🔒	💡
@typescript-eslint/no-redundant-type-constituents Disallow members of unions and intersections that do nothing or override type information	✅		💭
@typescript-eslint/no-require-imports Disallow invocation of require()
@typescript-eslint/no-this-alias Disallow aliasing this	✅
@typescript-eslint/no-type-alias Disallow type aliases
@typescript-eslint/no-unnecessary-boolean-literal-compare Disallow unnecessary equality comparisons against boolean literals	🔒	🔧	💭
@typescript-eslint/no-unnecessary-condition Disallow conditionals where the type is always truthy or always falsy	🔒	🔧	💭
@typescript-eslint/no-unnecessary-qualifier Disallow unnecessary namespace qualifiers		🔧	💭
@typescript-eslint/no-unnecessary-type-arguments Disallow type arguments that are equal to the default	🔒	🔧	💭
@typescript-eslint/no-unnecessary-type-assertion Disallow type assertions that do not change the type of an expression	✅	🔧	💭
@typescript-eslint/no-unnecessary-type-constraint Disallow unnecessary constraints on generic types	✅	💡
@typescript-eslint/no-unsafe-argument Disallow calling a function with a value with type any	✅		💭
@typescript-eslint/no-unsafe-assignment Disallow assigning a value with type any to variables and properties	✅		💭
@typescript-eslint/no-unsafe-call Disallow calling a value with type any	✅		💭
@typescript-eslint/no-unsafe-declaration-merging Disallow unsafe declaration merging	✅
@typescript-eslint/no-unsafe-enum-comparison Disallow comparing an enum value with a non-enum value	✅		💭
@typescript-eslint/no-unsafe-member-access Disallow member access on a value with type any	✅		💭
@typescript-eslint/no-unsafe-return Disallow returning a value with type any from a function	✅		💭
@typescript-eslint/no-useless-empty-export Disallow empty exports that don't change anything in a module file		🔧
@typescript-eslint/no-var-requires Disallow require statements except in import statements	✅
@typescript-eslint/non-nullable-type-assertion-style Enforce non-null assertions over explicit type casts	🎨	🔧	💭
@typescript-eslint/parameter-properties Require or disallow parameter properties in class constructors
@typescript-eslint/prefer-as-const Enforce the use of as const over literal type	✅	🔧 💡
@typescript-eslint/prefer-enum-initializers Require each enum member value to be explicitly initialized		💡
@typescript-eslint/prefer-for-of Enforce the use of for-of loop over the standard for loop where possible	🎨
@typescript-eslint/prefer-function-type Enforce using function types instead of interfaces with call signatures	🎨	🔧
@typescript-eslint/prefer-includes Enforce includes method over indexOf method	🔒	🔧	💭
@typescript-eslint/prefer-literal-enum-member Require all enum members to be literal values	🔒
@typescript-eslint/prefer-namespace-keyword Require using namespace keyword over module keyword to declare custom TypeScript modules	🎨	🔧
@typescript-eslint/prefer-nullish-coalescing Enforce using the nullish coalescing operator instead of logical assignments or chaining	🎨	💡	💭
@typescript-eslint/prefer-optional-chain Enforce using concise optional chain expressions instead of chained logical ands, negated logical ors, or empty objects	🎨	🔧 💡	💭
@typescript-eslint/prefer-readonly Require private members to be marked as readonly if they're never modified outside of the constructor		🔧	💭
@typescript-eslint/prefer-readonly-parameter-types Require function parameters to be typed as readonly to prevent accidental mutation of inputs			💭
@typescript-eslint/prefer-reduce-type-parameter Enforce using type parameter when calling Array#reduce instead of casting	🔒	🔧	💭
@typescript-eslint/prefer-regexp-exec Enforce RegExp#exec over String#match if no global flag is provided		🔧	💭
@typescript-eslint/prefer-return-this-type Enforce that this is used when only this type is returned	🔒	🔧	💭
@typescript-eslint/prefer-string-starts-ends-with Enforce using String#startsWith and String#endsWith over other equivalent methods of checking substrings	🎨	🔧	💭
@typescript-eslint/prefer-ts-expect-error Enforce using @ts-expect-error over @ts-ignore	🔒	🔧
@typescript-eslint/promise-function-async Require any function or method that returns a Promise to be marked async		🔧	💭
@typescript-eslint/require-array-sort-compare Require Array#sort calls to always provide a compareFunction			💭
@typescript-eslint/restrict-plus-operands Require both operands of addition to be the same type and be bigint, number, or string	✅		💭
@typescript-eslint/restrict-template-expressions Enforce template literal expressions to be of string type	✅		💭
@typescript-eslint/sort-type-constituents Enforce constituents of a type union/intersection to be sorted alphabetically		🔧 💡
@typescript-eslint/strict-boolean-expressions Disallow certain types in boolean expressions		🔧 💡	💭
@typescript-eslint/switch-exhaustiveness-check Require switch-case statements to be exhaustive with union type		💡	💭
@typescript-eslint/triple-slash-reference Disallow certain triple slash directives in favor of ES6-style import declarations	✅
@typescript-eslint/type-annotation-spacing Require consistent spacing around type annotations		🔧
@typescript-eslint/typedef Require type annotations in certain places
@typescript-eslint/unbound-method Enforce unbound methods are called with their expected scope	✅		💭
@typescript-eslint/unified-signatures Disallow two overloads that could be unified into one with a union or an optional/rest parameter	🔒

Extension Rules

In some cases, ESLint provides a rule itself, but it doesn't support TypeScript syntax; either it crashes, or it ignores the syntax, or it falsely reports against it. In these cases, we create what we call an extension rule; a rule within our plugin that has the same functionality, but also supports TypeScript.

Config Group

Metadata

Rule	Config	Fixer	Typed
@typescript-eslint/block-spacing Disallow or enforce spaces inside of blocks after opening block and before closing block		🔧
@typescript-eslint/brace-style Enforce consistent brace style for blocks		🔧
@typescript-eslint/comma-dangle Require or disallow trailing commas		🔧
@typescript-eslint/comma-spacing Enforce consistent spacing before and after commas		🔧
@typescript-eslint/default-param-last Enforce default parameters to be last
@typescript-eslint/dot-notation Enforce dot notation whenever possible	🎨	🔧	💭
@typescript-eslint/func-call-spacing Require or disallow spacing between function identifiers and their invocations		🔧
@typescript-eslint/indent Enforce consistent indentation		🔧
@typescript-eslint/init-declarations Require or disallow initialization in variable declarations
@typescript-eslint/key-spacing Enforce consistent spacing between property names and type annotations in types and interfaces		🔧
@typescript-eslint/keyword-spacing Enforce consistent spacing before and after keywords		🔧
@typescript-eslint/lines-around-comment Require empty lines around comments		🔧
@typescript-eslint/lines-between-class-members Require or disallow an empty line between class members		🔧
@typescript-eslint/no-array-constructor Disallow generic Array constructors	✅	🔧
@typescript-eslint/no-dupe-class-members Disallow duplicate class members
@typescript-eslint/no-empty-function Disallow empty functions	🎨
@typescript-eslint/no-extra-parens Disallow unnecessary parentheses		🔧
@typescript-eslint/no-extra-semi Disallow unnecessary semicolons		🔧
@typescript-eslint/no-implied-eval Disallow the use of eval()-like methods	✅		💭
@typescript-eslint/no-invalid-this Disallow this keywords outside of classes or class-like objects
@typescript-eslint/no-loop-func Disallow function declarations that contain unsafe references inside loop statements
@typescript-eslint/no-loss-of-precision Disallow literal numbers that lose precision	✅
@typescript-eslint/no-magic-numbers Disallow magic numbers
@typescript-eslint/no-redeclare Disallow variable redeclaration
@typescript-eslint/no-restricted-imports Disallow specified modules when loaded by import
@typescript-eslint/no-shadow Disallow variable declarations from shadowing variables declared in the outer scope
@typescript-eslint/no-throw-literal Disallow throwing literals as exceptions	🔒		💭
@typescript-eslint/no-unused-expressions Disallow unused expressions
@typescript-eslint/no-unused-vars Disallow unused variables	✅
@typescript-eslint/no-use-before-define Disallow the use of variables before they are defined
@typescript-eslint/no-useless-constructor Disallow unnecessary constructors	🔒
@typescript-eslint/object-curly-spacing Enforce consistent spacing inside braces		🔧
@typescript-eslint/padding-line-between-statements Require or disallow padding lines between statements		🔧
@typescript-eslint/quotes Enforce the consistent use of either backticks, double, or single quotes		🔧
@typescript-eslint/require-await Disallow async functions which have no await expression	✅		💭
@typescript-eslint/return-await Enforce consistent returning of awaited values		🔧 💡	💭
@typescript-eslint/semi Require or disallow semicolons instead of ASI		🔧
@typescript-eslint/space-before-blocks Enforce consistent spacing before blocks		🔧
@typescript-eslint/space-before-function-paren Enforce consistent spacing before function parenthesis		🔧
@typescript-eslint/space-infix-ops Require spacing around infix operators		🔧