--- title: Overview sidebar_label: Overview pagination_next: null pagination_prev: null slug: / --- `@typescript-eslint/eslint-plugin` comes with two rulesets you can extend from to pull in the recommended starting rules: - `'plugin:@typescript-eslint/recommended'`: recommended rules for code correctness that you can drop in without additional configuration. See [Linting](/docs/linting/linting) for more details. - `'plugin:@typescript-eslint/recommended-requiring-type-checking'` additional recommended rules that require type information. See [Linting](/docs/linting/type-linting) for more details. ## Supported Rules **Key**: :white_check_mark: = recommended, :wrench: = fixable, :thought_balloon: = requires type information | Name | Description | :white_check_mark: | :wrench: | :thought_balloon: | | ------------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------- | ------------------ | -------- | ----------------- | | [`@typescript-eslint/adjacent-overload-signatures`](./adjacent-overload-signatures.md) | Require that member overloads be consecutive | :white_check_mark: | | | | [`@typescript-eslint/array-type`](./array-type.md) | Requires using either `T[]` or `Array` for arrays | | :wrench: | | | [`@typescript-eslint/await-thenable`](./await-thenable.md) | Disallows awaiting a value that is not a Thenable | :white_check_mark: | | :thought_balloon: | | [`@typescript-eslint/ban-ts-comment`](./ban-ts-comment.md) | Bans `@ts-` comments from being used or requires descriptions after directive | :white_check_mark: | | | | [`@typescript-eslint/ban-tslint-comment`](./ban-tslint-comment.md) | Bans `// tslint:` comments from being used | | :wrench: | | | [`@typescript-eslint/ban-types`](./ban-types.md) | Bans specific types from being used | :white_check_mark: | :wrench: | | | [`@typescript-eslint/class-literal-property-style`](./class-literal-property-style.md) | Ensures that literals on classes are exposed in a consistent style | | :wrench: | | | [`@typescript-eslint/consistent-indexed-object-style`](./consistent-indexed-object-style.md) | Enforce or disallow the use of the record type | | :wrench: | | | [`@typescript-eslint/consistent-type-assertions`](./consistent-type-assertions.md) | Enforces consistent usage of type assertions | | | | | [`@typescript-eslint/consistent-type-definitions`](./consistent-type-definitions.md) | Consistent with type definition either `interface` or `type` | | :wrench: | | | [`@typescript-eslint/consistent-type-exports`](./consistent-type-exports.md) | Enforces consistent usage of type exports | | :wrench: | :thought_balloon: | | [`@typescript-eslint/consistent-type-imports`](./consistent-type-imports.md) | Enforces consistent usage of type imports | | :wrench: | | | [`@typescript-eslint/explicit-function-return-type`](./explicit-function-return-type.md) | Require explicit return types on functions and class methods | | | | | [`@typescript-eslint/explicit-member-accessibility`](./explicit-member-accessibility.md) | Require explicit accessibility modifiers on class properties and methods | | :wrench: | | | [`@typescript-eslint/explicit-module-boundary-types`](./explicit-module-boundary-types.md) | Require explicit return and argument types on exported functions' and classes' public class methods | | | | | [`@typescript-eslint/member-delimiter-style`](./member-delimiter-style.md) | Require a specific member delimiter style for interfaces and type literals | | :wrench: | | | [`@typescript-eslint/member-ordering`](./member-ordering.md) | Require a consistent member declaration order | | | | | [`@typescript-eslint/method-signature-style`](./method-signature-style.md) | Enforces using a particular method signature syntax. | | :wrench: | | | [`@typescript-eslint/naming-convention`](./naming-convention.md) | Enforces naming conventions for everything across a codebase | | | :thought_balloon: | | [`@typescript-eslint/no-base-to-string`](./no-base-to-string.md) | Requires that `.toString()` is only called on objects which provide useful information when stringified | | | :thought_balloon: | | [`@typescript-eslint/no-confusing-non-null-assertion`](./no-confusing-non-null-assertion.md) | Disallow non-null assertion in locations that may be confusing | | :wrench: | | | [`@typescript-eslint/no-confusing-void-expression`](./no-confusing-void-expression.md) | Requires expressions of type void to appear in statement position | | :wrench: | :thought_balloon: | | [`@typescript-eslint/no-dynamic-delete`](./no-dynamic-delete.md) | Disallow the delete operator with computed key expressions | | :wrench: | | | [`@typescript-eslint/no-empty-interface`](./no-empty-interface.md) | Disallow the declaration of empty interfaces | :white_check_mark: | :wrench: | | | [`@typescript-eslint/no-explicit-any`](./no-explicit-any.md) | Disallow usage of the `any` type | :white_check_mark: | :wrench: | | | [`@typescript-eslint/no-extra-non-null-assertion`](./no-extra-non-null-assertion.md) | Disallow extra non-null assertion | :white_check_mark: | :wrench: | | | [`@typescript-eslint/no-extraneous-class`](./no-extraneous-class.md) | Forbids the use of classes as namespaces | | | | | [`@typescript-eslint/no-floating-promises`](./no-floating-promises.md) | Requires Promise-like values to be handled appropriately | :white_check_mark: | | :thought_balloon: | | [`@typescript-eslint/no-for-in-array`](./no-for-in-array.md) | Disallow iterating over an array with a for-in loop | :white_check_mark: | | :thought_balloon: | | [`@typescript-eslint/no-inferrable-types`](./no-inferrable-types.md) | Disallows explicit type declarations for variables or parameters initialized to a number, string, or boolean | :white_check_mark: | :wrench: | | | [`@typescript-eslint/no-invalid-void-type`](./no-invalid-void-type.md) | Disallows usage of `void` type outside of generic or return types | | | | | [`@typescript-eslint/no-meaningless-void-operator`](./no-meaningless-void-operator.md) | Disallow the `void` operator except when used to discard a value | | :wrench: | :thought_balloon: | | [`@typescript-eslint/no-misused-new`](./no-misused-new.md) | Enforce valid definition of `new` and `constructor` | :white_check_mark: | | | | [`@typescript-eslint/no-misused-promises`](./no-misused-promises.md) | Avoid using promises in places not designed to handle them | :white_check_mark: | | :thought_balloon: | | [`@typescript-eslint/no-namespace`](./no-namespace.md) | Disallow the use of custom TypeScript modules and namespaces | :white_check_mark: | | | | [`@typescript-eslint/no-non-null-asserted-nullish-coalescing`](./no-non-null-asserted-nullish-coalescing.md) | Disallows using a non-null assertion in the left operand of the nullish coalescing operator | | | | | [`@typescript-eslint/no-non-null-asserted-optional-chain`](./no-non-null-asserted-optional-chain.md) | Disallows using a non-null assertion after an optional chain expression | :white_check_mark: | | | | [`@typescript-eslint/no-non-null-assertion`](./no-non-null-assertion.md) | Disallows non-null assertions using the `!` postfix operator | :white_check_mark: | | | | [`@typescript-eslint/no-parameter-properties`](./no-parameter-properties.md) | Disallow the use of parameter properties in class constructors | | | | | [`@typescript-eslint/no-require-imports`](./no-require-imports.md) | Disallows invocation of `require()` | | | | | [`@typescript-eslint/no-this-alias`](./no-this-alias.md) | Disallow aliasing `this` | :white_check_mark: | | | | [`@typescript-eslint/no-type-alias`](./no-type-alias.md) | Disallow the use of type aliases | | | | | [`@typescript-eslint/no-unnecessary-boolean-literal-compare`](./no-unnecessary-boolean-literal-compare.md) | Flags unnecessary equality comparisons against boolean literals | | :wrench: | :thought_balloon: | | [`@typescript-eslint/no-unnecessary-condition`](./no-unnecessary-condition.md) | Prevents conditionals where the type is always truthy or always falsy | | :wrench: | :thought_balloon: | | [`@typescript-eslint/no-unnecessary-qualifier`](./no-unnecessary-qualifier.md) | Warns when a namespace qualifier is unnecessary | | :wrench: | :thought_balloon: | | [`@typescript-eslint/no-unnecessary-type-arguments`](./no-unnecessary-type-arguments.md) | Enforces that type arguments will not be used if not required | | :wrench: | :thought_balloon: | | [`@typescript-eslint/no-unnecessary-type-assertion`](./no-unnecessary-type-assertion.md) | Warns if a type assertion does not change the type of an expression | :white_check_mark: | :wrench: | :thought_balloon: | | [`@typescript-eslint/no-unnecessary-type-constraint`](./no-unnecessary-type-constraint.md) | Disallows unnecessary constraints on generic types | :white_check_mark: | :wrench: | | | [`@typescript-eslint/no-unsafe-argument`](./no-unsafe-argument.md) | Disallows calling a function with an any type value | :white_check_mark: | | :thought_balloon: | | [`@typescript-eslint/no-unsafe-assignment`](./no-unsafe-assignment.md) | Disallows assigning any to variables and properties | :white_check_mark: | | :thought_balloon: | | [`@typescript-eslint/no-unsafe-call`](./no-unsafe-call.md) | Disallows calling an any type value | :white_check_mark: | | :thought_balloon: | | [`@typescript-eslint/no-unsafe-member-access`](./no-unsafe-member-access.md) | Disallows member access on any typed variables | :white_check_mark: | | :thought_balloon: | | [`@typescript-eslint/no-unsafe-return`](./no-unsafe-return.md) | Disallows returning any from a function | :white_check_mark: | | :thought_balloon: | | [`@typescript-eslint/no-var-requires`](./no-var-requires.md) | Disallows the use of require statements except in import statements | :white_check_mark: | | | | [`@typescript-eslint/non-nullable-type-assertion-style`](./non-nullable-type-assertion-style.md) | Prefers a non-null assertion over explicit type cast when possible | | :wrench: | :thought_balloon: | | [`@typescript-eslint/prefer-as-const`](./prefer-as-const.md) | Prefer usage of `as const` over literal type | :white_check_mark: | :wrench: | | | [`@typescript-eslint/prefer-enum-initializers`](./prefer-enum-initializers.md) | Prefer initializing each enums member value | | | | | [`@typescript-eslint/prefer-for-of`](./prefer-for-of.md) | 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-function-type`](./prefer-function-type.md) | Use function types instead of interfaces with call signatures | | :wrench: | | | [`@typescript-eslint/prefer-includes`](./prefer-includes.md) | Enforce `includes` method over `indexOf` method | | :wrench: | :thought_balloon: | | [`@typescript-eslint/prefer-literal-enum-member`](./prefer-literal-enum-member.md) | Require that all enum members be literal values to prevent unintended enum member name shadow issues | | | | | [`@typescript-eslint/prefer-namespace-keyword`](./prefer-namespace-keyword.md) | Require the use of the `namespace` keyword instead of the `module` keyword to declare custom TypeScript modules | :white_check_mark: | :wrench: | | | [`@typescript-eslint/prefer-nullish-coalescing`](./prefer-nullish-coalescing.md) | Enforce the usage of the nullish coalescing operator instead of logical chaining | | | :thought_balloon: | | [`@typescript-eslint/prefer-optional-chain`](./prefer-optional-chain.md) | Prefer using concise optional chain expressions instead of chained logical ands | | | | | [`@typescript-eslint/prefer-readonly`](./prefer-readonly.md) | Requires that private members are marked as `readonly` if they're never modified outside of the constructor | | :wrench: | :thought_balloon: | | [`@typescript-eslint/prefer-readonly-parameter-types`](./prefer-readonly-parameter-types.md) | Requires that function parameters are typed as readonly to prevent accidental mutation of inputs | | | :thought_balloon: | | [`@typescript-eslint/prefer-reduce-type-parameter`](./prefer-reduce-type-parameter.md) | Prefer using type parameter when calling `Array#reduce` instead of casting | | :wrench: | :thought_balloon: | | [`@typescript-eslint/prefer-regexp-exec`](./prefer-regexp-exec.md) | Enforce that `RegExp#exec` is used instead of `String#match` if no global flag is provided | | :wrench: | :thought_balloon: | | [`@typescript-eslint/prefer-return-this-type`](./prefer-return-this-type.md) | Enforce that `this` is used when only `this` type is returned | | :wrench: | :thought_balloon: | | [`@typescript-eslint/prefer-string-starts-ends-with`](./prefer-string-starts-ends-with.md) | Enforce the use of `String#startsWith` and `String#endsWith` instead of other equivalent methods of checking substrings | | :wrench: | :thought_balloon: | | [`@typescript-eslint/prefer-ts-expect-error`](./prefer-ts-expect-error.md) | Recommends using `@ts-expect-error` over `@ts-ignore` | | :wrench: | | | [`@typescript-eslint/promise-function-async`](./promise-function-async.md) | Requires any function or method that returns a Promise to be marked async | | :wrench: | :thought_balloon: | | [`@typescript-eslint/require-array-sort-compare`](./require-array-sort-compare.md) | Requires `Array#sort` calls to always provide a `compareFunction` | | | :thought_balloon: | | [`@typescript-eslint/restrict-plus-operands`](./restrict-plus-operands.md) | When adding two variables, operands must both be of type number or of type string | :white_check_mark: | | :thought_balloon: | | [`@typescript-eslint/restrict-template-expressions`](./restrict-template-expressions.md) | Enforce template literal expressions to be of string type | :white_check_mark: | | :thought_balloon: | | [`@typescript-eslint/sort-type-union-intersection-members`](./sort-type-union-intersection-members.md) | Enforces that members of a type union/intersection are sorted alphabetically | | :wrench: | | | [`@typescript-eslint/strict-boolean-expressions`](./strict-boolean-expressions.md) | Restricts the types allowed in boolean expressions | | :wrench: | :thought_balloon: | | [`@typescript-eslint/switch-exhaustiveness-check`](./switch-exhaustiveness-check.md) | Exhaustiveness checking in switch with union type | | | :thought_balloon: | | [`@typescript-eslint/triple-slash-reference`](./triple-slash-reference.md) | Sets preference level for triple slash directives versus ES6-style import declarations | :white_check_mark: | | | | [`@typescript-eslint/type-annotation-spacing`](./type-annotation-spacing.md) | Require consistent spacing around type annotations | | :wrench: | | | [`@typescript-eslint/typedef`](./typedef.md) | Requires type annotations to exist | | | | | [`@typescript-eslint/unbound-method`](./unbound-method.md) | Enforces unbound methods are called with their expected scope | :white_check_mark: | | :thought_balloon: | | [`@typescript-eslint/unified-signatures`](./unified-signatures.md) | Warns for any two overloads that could be unified into one by using 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. **Key**: :white_check_mark: = recommended, :wrench: = fixable, :thought_balloon: = requires type information | Name | Description | :white_check_mark: | :wrench: | :thought_balloon: | | -------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------ | ------------------ | -------- | ----------------- | | [`@typescript-eslint/brace-style`](./brace-style.md) | Enforce consistent brace style for blocks | | :wrench: | | | [`@typescript-eslint/comma-dangle`](./comma-dangle.md) | Require or disallow trailing comma | | :wrench: | | | [`@typescript-eslint/comma-spacing`](./comma-spacing.md) | Enforces consistent spacing before and after commas | | :wrench: | | | [`@typescript-eslint/default-param-last`](./default-param-last.md) | Enforce default parameters to be last | | | | | [`@typescript-eslint/dot-notation`](./dot-notation.md) | enforce dot notation whenever possible | | :wrench: | :thought_balloon: | | [`@typescript-eslint/func-call-spacing`](./func-call-spacing.md) | Require or disallow spacing between function identifiers and their invocations | | :wrench: | | | [`@typescript-eslint/indent`](./indent.md) | Enforce consistent indentation | | :wrench: | | | [`@typescript-eslint/init-declarations`](./init-declarations.md) | require or disallow initialization in variable declarations | | | | | [`@typescript-eslint/keyword-spacing`](./keyword-spacing.md) | Enforce consistent spacing before and after keywords | | :wrench: | | | [`@typescript-eslint/lines-between-class-members`](./lines-between-class-members.md) | Require or disallow an empty line between class members | | :wrench: | | | [`@typescript-eslint/no-array-constructor`](./no-array-constructor.md) | Disallow generic `Array` constructors | :white_check_mark: | :wrench: | | | [`@typescript-eslint/no-dupe-class-members`](./no-dupe-class-members.md) | Disallow duplicate class members | | | | | [`@typescript-eslint/no-duplicate-imports`](./no-duplicate-imports.md) | Disallow duplicate imports | | | | | [`@typescript-eslint/no-empty-function`](./no-empty-function.md) | Disallow empty functions | :white_check_mark: | | | | [`@typescript-eslint/no-extra-parens`](./no-extra-parens.md) | Disallow unnecessary parentheses | | :wrench: | | | [`@typescript-eslint/no-extra-semi`](./no-extra-semi.md) | Disallow unnecessary semicolons | :white_check_mark: | :wrench: | | | [`@typescript-eslint/no-implied-eval`](./no-implied-eval.md) | Disallow the use of `eval()`-like methods | :white_check_mark: | | :thought_balloon: | | [`@typescript-eslint/no-invalid-this`](./no-invalid-this.md) | Disallow `this` keywords outside of classes or class-like objects | | | | | [`@typescript-eslint/no-loop-func`](./no-loop-func.md) | Disallow function declarations that contain unsafe references inside loop statements | | | | | [`@typescript-eslint/no-loss-of-precision`](./no-loss-of-precision.md) | Disallow literal numbers that lose precision | :white_check_mark: | | | | [`@typescript-eslint/no-magic-numbers`](./no-magic-numbers.md) | Disallow magic numbers | | | | | [`@typescript-eslint/no-redeclare`](./no-redeclare.md) | Disallow variable redeclaration | | | | | [`@typescript-eslint/no-restricted-imports`](./no-restricted-imports.md) | Disallow specified modules when loaded by `import` | | | | | [`@typescript-eslint/no-shadow`](./no-shadow.md) | Disallow variable declarations from shadowing variables declared in the outer scope | | | | | [`@typescript-eslint/no-throw-literal`](./no-throw-literal.md) | Disallow throwing literals as exceptions | | | :thought_balloon: | | [`@typescript-eslint/no-unused-expressions`](./no-unused-expressions.md) | Disallow unused expressions | | | | | [`@typescript-eslint/no-unused-vars`](./no-unused-vars.md) | Disallow unused variables | :white_check_mark: | | | | [`@typescript-eslint/no-use-before-define`](./no-use-before-define.md) | Disallow the use of variables before they are defined | | | | | [`@typescript-eslint/no-useless-constructor`](./no-useless-constructor.md) | Disallow unnecessary constructors | | | | | [`@typescript-eslint/object-curly-spacing`](./object-curly-spacing.md) | Enforce consistent spacing inside braces | | :wrench: | | | [`@typescript-eslint/padding-line-between-statements`](./padding-line-between-statements.md) | require or disallow padding lines between statements | | :wrench: | | | [`@typescript-eslint/quotes`](./quotes.md) | Enforce the consistent use of either backticks, double, or single quotes | | :wrench: | | | [`@typescript-eslint/require-await`](./require-await.md) | Disallow async functions which have no `await` expression | :white_check_mark: | | :thought_balloon: | | [`@typescript-eslint/return-await`](./return-await.md) | Enforces consistent returning of awaited values | | :wrench: | :thought_balloon: | | [`@typescript-eslint/semi`](./semi.md) | Require or disallow semicolons instead of ASI | | :wrench: | | | [`@typescript-eslint/space-before-function-paren`](./space-before-function-paren.md) | Enforces consistent spacing before function parenthesis | | :wrench: | | | [`@typescript-eslint/space-infix-ops`](./space-infix-ops.md) | This rule is aimed at ensuring there are spaces around infix operators. | | :wrench: | |