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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

Rule 🔒🔧 🛠💭
@typescript-eslint/adjacent-overload-signatures
Require that member overloads be consecutive
@typescript-eslint/array-type
Require 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 directive
@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-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 assertion
🔧
@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-implicit-any-catch
Disallow usage of the implicit any type in catch clauses
🔧 🛠
@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-namespace
Disallow custom TypeScript modules and 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-parameter-properties
Disallow the use of parameter properties in class constructors
@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-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 chaining
🔒 🛠💭
@typescript-eslint/prefer-optional-chain
Enforce using concise optional chain expressions instead of chained logical ands
🔒 🛠
@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 have type number or string
💭
@typescript-eslint/restrict-template-expressions
Enforce template literal expressions to be of string type
💭
@typescript-eslint/sort-type-union-intersection-members
Enforce members 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.

Rule 🔒🔧 🛠💭
@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/keyword-spacing
Enforce consistent spacing before and after keywords
🔧
@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-duplicate-imports
Disallow duplicate imports
@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
🔧