export default type

Search Terms

export default type

Suggestion

Allow export default for type.

Use Cases

It would be very nice to have export default type to match with other default exports such as classes and interfaces.

Right now it looks very inconsistent to be able to export anything as default and only types with named export:

export default class MyClass {}
export default interface MyInterface {}
export type MyType = {}

The only way to achieve this now is to use annoying workaround:

type X = number | string

export { X as default }

This may cause confusion for newbies as there are no clear reasons why classes and interfaces can be exported as default, but not the types.

Examples

// x.ts
export default type X = {}

// main.ts
import X from './x'

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

(not sure on the last)

Der Issue enthält Syntaxbeispiele zum Hinzufügen von Default-Exports zu Typen, nennt aber keine Quelldateien, Tests oder Einstiegspunkte. Beginne damit, die bestehende Behandlung von Default-Exports für Klassen und Interfaces nachzuverfolgen, und ermittle dann, für welches Verhalten von parser, checker und emit eine Abdeckung erforderlich wäre; als abgeschlossen gilt die Arbeit, wenn die vorgeschlagene Syntax mit dem gezeigten Import funktioniert, ohne das emittierte JavaScript zu ändern.