106 lines
2.4 KiB
Plaintext
106 lines
2.4 KiB
Plaintext
---
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description: 'Enforce consistent usage of type exports.'
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---
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> 🛑 This file is source code, not the primary documentation location! 🛑
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>
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> See **https://typescript-eslint.io/rules/consistent-type-exports** for documentation.
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TypeScript allows specifying a `type` keyword on exports to indicate that the export exists only in the type system, not at runtime.
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This allows transpilers to drop exports without knowing the types of the dependencies.
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> See [Blog > Consistent Type Exports and Imports: Why and How](/blog/consistent-type-imports-and-exports-why-and-how) for more details.
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## Examples
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<!--tabs-->
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### ❌ Incorrect
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```ts
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interface ButtonProps {
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onClick: () => void;
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}
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class Button implements ButtonProps {
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onClick = () => console.log('button!');
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}
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export { Button, ButtonProps };
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```
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### ✅ Correct
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```ts
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interface ButtonProps {
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onClick: () => void;
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}
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class Button implements ButtonProps {
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onClick = () => console.log('button!');
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}
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export { Button };
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export type { ButtonProps };
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```
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## Options
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### `fixMixedExportsWithInlineTypeSpecifier`
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When this is set to true, the rule will autofix "mixed" export cases using TS 4.5's "inline type specifier".
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If you are using a TypeScript version less than 4.5, then you will not be able to use this option.
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For example the following code:
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```ts
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const x = 1;
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type T = number;
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export { x, T };
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```
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With `{fixMixedExportsWithInlineTypeSpecifier: true}` will be fixed to:
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```ts
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const x = 1;
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type T = number;
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export { x, type T };
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```
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With `{fixMixedExportsWithInlineTypeSpecifier: false}` will be fixed to:
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```ts
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const x = 1;
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type T = number;
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export type { T };
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export { x };
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```
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<!--tabs-->
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### ❌ Incorrect
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```ts option='{ "fixMixedExportsWithInlineTypeSpecifier": true }'
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export { Button } from 'some-library';
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export type { ButtonProps } from 'some-library';
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```
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### ✅ Correct
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```ts option='{ "fixMixedExportsWithInlineTypeSpecifier": true }'
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export { Button, type ButtonProps } from 'some-library';
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```
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## When Not To Use It
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If you use `--isolatedModules` the compiler would error if a type is not re-exported using `export type`.
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This rule may be less useful in those cases.
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If you specifically want to use both export kinds for stylistic reasons, or don't wish to enforce one style over the other, you can avoid this rule.
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However, keep in mind that inconsistent style can harm readability in a project.
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We recommend picking a single option for this rule that works best for your project.
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