Lib mode doesn't export types

[darklight9811]

Describe the bug

I'm using vitejs to build a react typescript library, I started building it with a plain rollup, but decided to migrate, so I have put everything accordingly. Fixed some bugs, added some packages, but when I export it, it doesn't export the typings (.d.ts) along with the es and umd files, even if I set declarations to true inside of the tsconfig. But it does export successfully both files.

I tried tweaking rollup but to no avail, and also couldn't find anything related to this in the issues or google at all.

Reproduction

Install vite with the "react-ts" template, follow the documentation steps to use lib mode, make a simple component and export it from the output file, and build it.

System Info

Output of npx envinfo --system --npmPackages vite,@vitejs/plugin-vue --binaries --browsers:

  System:
    OS: Windows 10 10.0.18363
    CPU: (8) x64 Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz
    Memory: 10.24 GB / 15.96 GB
  Binaries:
    Node: 14.3.0 - C:\Program Files\nodejs\node.EXE
    Yarn: 1.14.0 - D:\programas\laragon\bin\yarn\bin\yarn.CMD
    npm: 5.7.1 - ~\node_modules\.bin\npm.CMD
  Browsers:
    Chrome: 89.0.4389.128
    Edge: Spartan (44.18362.1474.0)
    Internet Explorer: 11.0.18362.1

Used package manager: yarn

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[Shinigami92]

Have you checked noEmit in tsconfig.json?

vite/packages/create-app/template-react-ts/tsconfig.json

Line 16 in 8dbebee

"noEmit": true,

This doesn't work together with declaration: true
https://www.typescriptlang.org/tsconfig#noEmit

[darklight9811]

Just checked, same thing, exported files:

[keelii]

You can use tsc command to generate a single bundled declaration file, like this:

{
    "build:types": "tsc -m amd -t ESNext -d --isolatedModules false  --moduleResolution node --esModuleInterop --jsx react --outFile dist/index.js src/main.ts && rm -rf dist/index.js ",

}

[darklight9811]

@keelii, but shouldn't vite provide this solution by default since it natively supports typescript?

[keelii]

When vite do this for you, it's not cheap, and if you do it by using tsc, It is truly more natively.

Because even if you use tsc, it's not so fluently. you will need concat to a single d.ts file which is not directly supported will in typescript, you need some tricks to let it work.

[Shinigami92]

Mh seems that it was already requested some time ago #2049

IMO it may make sense to generate declaration files in library mode, cause a published library should serve declarations. That just make the ecosystem a better place.

[darklight9811]

@Shinigami92, any dates or updates on when this would go to vitejs? That's the only thing that is preventing me from using on my company.

[Shinigami92]

@darklight9811 I don't know if there is currently an open PR, if not please feel free to jump in and create one 🙂

[patak-dev]

But even without this in core, this shouldn't prevent you to use it as you can generate the types on the side as was shown in the comments in this issue.

[darklight9811]

@patak-js, I don't know if I'm doing something wrong, but that command is not working and tweaking it also didn't work for me.

[Shinigami92]

@darklight9811 also tried this? #2989 (comment)

[samwightt]

Just tried to use Vite for a serious project at my company and this is preventing me from using it as well. Generating type definitions is something that should be supported by default, especially when the Typescript support in Vite is as good as it is already. Really disappointed that this hasn't been considered as a standard feature so that devs don't have to deal with low-quality workarounds.

[Shinigami92]

@samwightt As I already wrote here: #2989 (comment)

I'm sorry for you that you may have a misunderstanding about how open source works 🙁
But we give you everything you need to do a PR and nothing stops you from providing this much sought-after feature/fix
Do the world a favor and establish it for the entire community
And in the end, we're grateful for you resolving an issue the community had with Vite
Just assuming something should be supported right away and then being frustrated that it isn't and then doing nothing doesn't help anyone 🤷

[axelthat]

You can use https://github.com/egoist/tsup.

Example usage,

{
    "scripts": {
        "build": "tsup index.ts --format esm,cjs,iife --dts --minify"
    }
}

The --dts flag generates the types automatically.

[moljac024]

I understand the reasoning behind not doing this but I think it should be reconsidered. If Vite did this by default it would be a sort of pit of success that would benefit the broader JS/TS community. If it's not the default and people start using Vite to build libraries I imagine we will have lots of them published without types. That in turn will lead to a lot of churn and lots of github issues being created (in the respective libraries).

[Shinigami92]

@Sanjade, I can't get it to work with sass files, any idea how?

What does sass have to do with TypeScript declarations?! Could you explain a bit?

[darklight9811]

@Shinigami92 , sass files are generating css modules that can be exported and are dynamically typed.....

[samwightt]

If it's not the default and people start using Vite to build libraries I imagine we will have lots of them published without types.

This. Currently I'm actively discouraging people in my network from using Vite for libraries. Not having this on by default, especially when everything else in library mode just works, will objectively make the JS ecosystem worse. Usage of Typescript is only growing, so it would be good for Vite to be a good citizen and support this by default.

I'm not angry or annoyed that this is not the default, and I'm not expecting any work to be done to get this feature working. I just want to make sure that maintainers understand how big of a deal this feature is, and that not having it is a really glaring oversight when the rest of library mode is as polished as it is.

[Shinigami92]

@Sanjade Do you like to create a feature request issue for this? Then we have a fresh new issue and we can better track it 🙂

[nihalgonsalves]

Moved to #3461