deno types to output typings to a single file

[ebebbington]

What

As it stands, there doesn't seem to be a way to generate typings for a file, or files, using Deno. It might be possible with Deno.emit, using the 2nd argument (CompilerOptions), but i haven't checked this and I'm not too confident it can.

It also seems like deno types could be expanded upon, ie there's a great opportunity to expand upon this subcommand.

But what I propose is for deno types (and ideally a programatic way as well) to create the typings for the given file or directory that outputs to a single file

How

$ deno types src/mod.ts >> dist/mod.d.ts

await Deno.emit("./src/mod.ts", { typings: true })

Why

Well say I have a project that uses typescript. I plan to move over from Node to Deno, but I need typings. It seems impossible to do this with Deno, halting on that projects progress to make the beautiful journey of moving to Deno. This issue. is specifically with emitting a bundled .d.ts file.

Whilst I can use Deno.emit(file, { compilerOptions: { declaration: true }}), it still doesn't provide the bundled typings

Example

Here is an example, of me wanting to create a single bundled .d.ts file using the emit method, but it not actually providing typings:

// src/mod.ts
export * from "./something.ts"
export * from "./test.ts"

// compile.ts
const stuff = await Deno.emit("./src/mod.ts", {
  compilerOptions: {
    "declaration": true,
    "emitDeclarationOnly": true,
  }
})
const keys = Object.keys(stuff.files)
const key = keys.find(k => k.includes("mod.ts.d.ts")) as string
console.log(stuff.files[key])

/// <amd-module name="file:///.../.../tmp/src/mod.ts" />
export * from "./something.ts";
export * from "./test.ts";

As you can see, it doesn't provide any typings

[0kku]

Specifically, interoperability between Deno and TSC seems unachievable at present. Deno doesn't understand TSC's imports, nor TSC's .d.ts files because those also use the incorrect file extensions. On the other hand, TSC doesn't understand Deno's imports. There doesn't even seem to be any tools out there that would allow automating converting between the two formats. Ideally, you'd be able to bundle the typings of a project into a single .d.ts file in order to avoid the importing conflicts and allow you to be able to use the same code base for both Deno and TSC consumers.

[kitsonk]

Duplicate of #3385

(You can already set declaration: true in the compiler options in Deno.emit() for single file declarations, just like you would with tsc)

[jespertheend]

Does declaration: true still work? It doesn't seem to do anything, and it appears in a list of ignored options:

deno/cli/config_file.rs

Lines 86 to 90 in 1fb5858

	pub const IGNORED_COMPILER_OPTIONS: &[&str] = &[
	"allowSyntheticDefaultImports",
	"allowUmdGlobalAccess",
	"baseUrl",
	"declaration",

[jespertheend]

Oh never mind, it seems declaration: true does in fact do something. But if you try to emit the same file a second time, it keeps emitting d.ts files regardless of your declaration setting. Only after you clear the Deno cache will it stop emitting them.