Parcel: Typescript declaration files

[Robinfr]

Currently the TypeScript declaration files are not generated even when enabled in the tsconfig.json, would be nice if this could also be generated when building.

[tomtobac]

Any updates?

[fathyb]

Blocked by #465, no type-checking = no declarations. You can open an issue in the TypeScript plugin repo or wait for the plugin to be integrated in Parcel's core.

[mohsen1]

You can use tsc to generate type declarations independent of Parcel. Since Parcel is not doing the type-checking it's good to run tsc anyways.

[vincentfiestada]

Is it possible to generate type definitions for projects that use both Typescript and ReactJS? Using tsc on its own doesn't work, since the TSX needs to be parsed as well. Normally, I would use webpack, but then what would be the point of Parcel?
So, is there a way for the files to go through the normal Parcel pipeline (Babel, etc.) before going through the Typescript compiler?

[vincentfiestada]

It looks like the previous errors were actually just legitimate errors being emitted by the compiler. They were being suppressed by parcel.

I ended up running parcel and then running the Typescript compiler to get declaration files, as suggested by @mohsen1

[laosb]

Can't believe not yet implemented after 1 year and a half.

[DeMoorJasper]

@laosb you can just run tsc for typechecking and typedefinitions...

Parcel 2 supports typechecking, not entirely sure how type definition generation in a bundler works as I've never needed that before. If I'd know how that works I would be able to implement it for Parcel 2.

[Xiphe]

any updates here?

Would be great if we could use Parcel 2 to bundle node packages and include type declarations.

[DeMoorJasper]

This is already part of Parcel 2

[klemenoslaj]

This is already part of Parcel 2

I am just trying out Parcel 2. I configured my tsconfig.json to generate declarations.
Worth mentioning I am using latest nightly release of parcel with tsc transformer (parcel 2 to my big surprise uses babel typescript as a default).

Is your statement still valid?

[mischnic]

Something like this will generate the typing at dist/types.d.ts:

{
    "main": "dist/index.js"
    "types": "dist/index.d.ts"
    "scripts": {
        "build": "parcel build src/index.js"
    }
}

[klemenoslaj]

@mischnic you mean just having types in package.json should be enough?

I did try it tho, but am not getting it still 🤔

[mischnic]

@mischnic you mean just having types in package.json should be enough?

Yes.

I did try it tho, but am not getting it still 🤔

can you open a new issue with a code sample?

[klemenoslaj]

can you open a new issue with a code sample?

Will do :+1:

Trying for the second time I get:

@parcel/namer-default: Target "types" declares an output file path of "dist/index.d.ts" which does not match the compiled bundle type "js".

[mischnic]

@parcel/namer-default: Target "types" declares an output file path of "dist/index.d.ts" which does not match the compiled bundle type "js".

I have seen this being reported but wasn't able to reproduce it myself...

[dsedmak]

Seems like this is still an issue. I can reproduce this reliably on a fresh project using parcel@nightly.

If we do not have a .parcelrc file or have one that simply extends the default config adding a types entry to package.json causes the declarations to be generated.

With the following .parcelrc:

{
  "extends": "@parcel/config-default",
  "transformers": {
    "*.{ts,tsx}": ["@parcel/transformer-babel"]
  }
}

We get the error: @parcel/namer-default: Target "main" declares an output file path of "dist/index.js" which does not match the compiled bundle type "ts".

With the following .parcelrc:

{
  "extends": "@parcel/config-default",
  "transformers": {
    "*.{ts,tsx}": ["@parcel/transformer-typescript-tsc"]
  }
}

We get the error: @parcel/namer-default: Target "types" declares an output file path of "dist/index.d.ts" which does not match the compiled bundle type "js".

[mischnic]

"*.{ts,tsx}": ["@parcel/transformer-babel"]

You're missing @parcel/transformer-js. (And that configuration isn't needed since this is what the default config does).

Target "types" declares an output file path of "dist/index.d.ts" which does not match the compiled bundle type "js"

Please see https://github.com/parcel-bundler/parcel/issues/4666. Looking into it now...