Emit typescript interfaces?

[arabold]

I'm able to successfully create a OpenAPI spec from my TypeSpec, as well as JSON Schema files. But how about something as simple as plain TypeScript interfaces? Is there a default emitter that can create these?

I'm aware that I could do TypeSpec -> JSON Schema -> TypeScript, and I tried that already, but that seems a bit convoluted 🤨

// main.tsp
model Pet {}
model Person {
  pet: Pet;
}

would become

// models.d.ts
export interface Pet {}
export interface Person {
  pet: Pet;
}

[bterlson]

I believe this should be coming soon as part of our Rest client emitter work, though I can't say for sure. We definitely intend to have "model emitters" in all languages we support eventually.

If it's interesting or useful, we have a test emitter that does this, which you could perhaps use. Just note that it's just for testing purposes and you will have to copy/paste the code. You can find it here: https://github.com/microsoft/typespec/blob/main/packages/compiler/test/emitter-framework/typescript-emitter.ts

[arabold]

Thank you for the reference. Indeed the example does what I was looking for 👍 Based on that I was able to create my own emitter that can create NestJS DTOs including class-validator decorators. Amazingly easy to use. I'm sold!

[bterlson]

Hey cool, welcome to the world of custom codegen 😁

Just to warn you, so you're not surprised - we are working on a revamp of the emitter framework to, among other things, better support taking a typescript interface emitter library like you copy/pasted and layer in special behavior (like creating NestJS DTOs), and that may entail some amount of churn in these APIs. We will of course try not to break anything if at all possible.

[seidtgeist]

@bterlson That sounds super useful! Is it possible to follow the progress of that effort somewhere?

[crowbait]

Since this is the only reasonable Google result when searching for TS interfaces from TSP, I'll stick this here.

I have started work on a very simple emitter, which is capable of transforming at least basic TSP models to TypeScript interfaces.
It is currently quite tailored to what I need from it, but I'd be happy to work on it more and also it may be of some use for simpler projects out there, so I figured I'd share.

https://github.com/crowbait/typespec-typescript-emitter

It can also generate a TS object based on ops when using the HTTP library, which can help writing things like abstracted API wrappers (which is my specific use case and why I started on this in the first place). May be a bit specific, but still, might help someone.

[mcchrish]

There is also this https://www.npmjs.com/package/@azure-tools/typespec-ts. I don't use it personally but just found it while searching for typescript emitters.

[otomad]

There is also this https://www.npmjs.com/package/@azure-tools/typespec-ts. I don't use it personally but just found it while searching for typescript emitters.

I tried this, however it generates extra REST API code.