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consistent-type-imports

Enforce consistent usage of type imports.

🔧

Some problems reported by this rule are automatically fixable by the --fix ESLint command line option.

TypeScript allows specifying a type keyword on imports to indicate that the export exists only in the type system, not at runtime. This allows transpilers to drop imports without knowing the types of the dependencies.

See Blog > Consistent Type Exports and Imports: Why and How for more details.

.eslintrc.cjs
module.exports = {
  "rules": {
    "@typescript-eslint/consistent-type-imports": "error"
  }
};

Try this rule in the playground ↗

Options​

This rule accepts the following options:

type Options = [
  {
    disallowTypeAnnotations?: boolean;
    fixStyle?: 'inline-type-imports' | 'separate-type-imports';
    prefer?: 'no-type-imports' | 'type-imports';
  },
];

const defaultOptions: Options = [
  {
    prefer: 'type-imports',
    disallowTypeAnnotations: true,
    fixStyle: 'separate-type-imports',
  },
];

prefer​

This option defines the expected import kind for type-only imports. Valid values for prefer are:

  • type-imports will enforce that you always use import type Foo from '...' except referenced by metadata of decorators. It is the default.
  • no-type-imports will enforce that you always use import Foo from '...'.

Examples of correct code with {prefer: 'type-imports'}, and incorrect code with {prefer: 'no-type-imports'}.

import type { Foo } from 'Foo';
import type Bar from 'Bar';
type T = Foo;
const x: Bar = 1;
Open in Playground

Examples of incorrect code with {prefer: 'type-imports'}, and correct code with {prefer: 'no-type-imports'}.

import { Foo } from 'Foo';
import Bar from 'Bar';
type T = Foo;
const x: Bar = 1;
Open in Playground

fixStyle​

This option defines the expected type modifier to be added when an import is detected as used only in the type position. Valid values for fixStyle are:

  • separate-type-imports will add the type keyword after the import keyword import type { A } from '...'. It is the default.
  • inline-type-imports will inline the type keyword import { type A } from '...' and is only available in TypeScript 4.5 and onwards. See documentation here.
import { Foo } from 'Foo';
import Bar from 'Bar';
type T = Foo;
const x: Bar = 1;
Open in Playground

disallowTypeAnnotations​

If true, type imports in type annotations (import()) are not allowed. Default is true.

Examples of incorrect code with {disallowTypeAnnotations: true}:

type T = import('Foo').Foo;
const x: import('Bar') = 1;
Open in Playground

Caveat: @decorators + experimentalDecorators: true + emitDecoratorMetadata: true​

note

If you are using experimentalDecorators: false (eg TypeScript v5.0's stable decorators) then the rule will always report errors as expected. This caveat only applies to experimentalDecorators: true

The rule will not report any errors in files that contain decorators when both experimentalDecorators and emitDecoratorMetadata are turned on.

See Blog > Changes to consistent-type-imports when used with legacy decorators and decorator metadata for more details.

If you are using type-aware linting then we will automatically infer your setup from your tsconfig and you should not need to configure anything. Otherwise you can explicitly tell our tooling to analyze your code as if the compiler option was turned on by setting both parserOptions.emitDecoratorMetadata = true and parserOptions.experimentalDecorators = true.

Comparison with importsNotUsedAsValues / verbatimModuleSyntax​

verbatimModuleSyntax was introduced in TypeScript v5.0 (as a replacement for importsNotUsedAsValues). This rule and verbatimModuleSyntax mostly behave in the same way. There are a few behavior differences:

Situationconsistent-type-imports (ESLint)verbatimModuleSyntax (TypeScript)
Unused importsIgnored (consider using @typescript-eslint/no-unused-vars)Type error
Usage with emitDecoratorMetadata & experimentalDecorationsIgnores files that contain decoratorsReports on files that contain decorators
Failures detectedDoes not fail tsc build; can be auto-fixed with --fixFails tsc build; cannot be auto-fixed on the command-line
import { type T } from 'T';TypeScript will emit nothing (it "elides" the import)TypeScript emits import {} from 'T'

Because there are some differences, using both this rule and verbatimModuleSyntax at the same time can lead to conflicting errors. As such we recommend that you only ever use one or the other -- never both.

When Not To Use It​

If you specifically want to use both import kinds for stylistic reasons, or don't wish to enforce one style over the other, you can avoid this rule.

However, keep in mind that inconsistent style can harm readability in a project. We recommend picking a single option for this rule that works best for your project.

Resources​