Typescript: Support `--declarationOutFile` for bundling declarations for commonjs and es6 modules

[raybooysen]

This is very similar to #8305.

In our world we are using webpack to bundle our typescript library which has many levels of nesting. For example:

mylib\
  services\
    index.ts
    service1.ts
  foo\
     bar\
       index.ts
       barImpl.ts

At the moment our current approach is to export everything into one top-level index.ts which means consumers lose the nesting and we have to write the .d.ts files ourselves

Ideally we'd like consumers to import modules like this (and avoid a single index.ts file at the top level that exports everything in a non-nested structure):

import { service1 } from 'myLib/services

However it is not obvious from the documentation how to write a .d.ts file that supports this layout when this is how the webpack bundle is structured. As a second part, how can I have TS auto-generate the .d.ts files for us so that we can have a single definition file for our bundled JS

[basarat]

As a second part, how can I have TS auto-generate the .d.ts files for us so that we can have a single definition file for our bundled JS

Suggestion: Separate what webpack does with what tsc does:

• TSC : compiles .ts files to .js + .d.ts files.
• Webpack: Bundles these .js files in a bundle.js

This way your published module should contain : bundle.js, all the .js, all the .d.ts And people get to chose if they use bundle.js (not webpack user) or all the .js + all the .d.ts (webpack user)

I might be wrong :rose:

[mhegazy]

Does my sample in https://github.com/Microsoft/TypeScript/issues/8305#issuecomment-214815674 address the issue? if no, why not?

[raybooysen]

@mhegazy not exactly.

Your sample shows how to consume npm-libraries. As a library developer, using webpack to bundle, what is the best process to expose modules that "match" the folder listing and at the same time generate a single .d.ts file that includes the definitions for these bundled javascript modules.

[mhegazy]

i see. that is not a supported feature now. i would assume you want to have a --declarationFile that will bundle all your module declarations, but not your js output (currently --outFile bundles both .js and .d.ts output). is this accurate?

[raybooysen]

Yes, I think that is accurate. I think this is a common workflow, where TS developers will bundle a production bundle but still want to provide a d.ts file for other typescript consumers.

Happy to take advice on other alternatives.

[mhegazy]

thanks, updating the title to reflect the request.

PRs are welcomed.

[desjoerd]

Any updates on this?

[cesarvarela]

I'm just realizing that Typescript isn't very node.js developer friendly.

[mhegazy]

I'm just realizing that Typescript isn't very node.js developer friendly.

curious to know why is that.

[simonsarris]

@mhegazy I came to this issue thinking something similar, but that TypeScript is not very JS library developer friendly. It is not easy or obvious how to create a single .js file to use as a library on the web from several .ts classes, while this is trivial to do with plain JavaScript and requires no tools. TypeScript seems to require a lot of external tools to make projects like that work. In this case at least webpack is necessary to produce such single-file output, which really surprised me going in to TypeScript. (Or if not webpack, writing a script to strip the import/export from each file and concat all your .ts files before tsc runs)

The issue here for developers of web libraries is the other side of that coin. If I want to create a single .js file to use on the web as a library, I have to do something totally different to make a single .d.ts file. Specifying outFile won't work if your module is "commonjs", so something like declarationOutFile might be nice.

[LeonardSpencer]

Any update on this?

[mhegazy]

Any update on this?

The issue is marked as Accepting PRs. so PRs are welcomed.

[dwasyluk]

Monthly checking for any updates on this :)

[mtford90]

Pwetty pwetty pweaseee

[darren-dev]

New year update?

[raybooysen]

Closing as a dupe of #4433