TypeScript build tool that maps require('mymodule/foo') into './src/foo.ts'

[papb]

Rewording the request by @lifeiscontent here:

Consider the following TypeScript project that will be distributed as a npm package:

.
├── package.json
├── src
│   ├── index.ts
│   └── utils.ts
├── tsconfig.json
└── yarn.lock

Compiling this will generate ./dist/index.js and ./dist/utils.js. To import the module, require('the-module') works as long as the main field of package.json is setup correctly, which is fine and very common to do. However, there is no good way to also provide ./utils.ts directly as require('the-module/utils'). Instead, people would have to do require('the-module/dist/utils') which is ugly.

There could be a command line utility to be called within prepack that:

• Reorders everything in a way that automatically puts everything available there directly; or
• (hackier) Injects a smart call to pirates on the index.js file.

Thoughts?

[Richienb]

This can be done in the resolveId part of a rollup plugin.

[papb]

Hi @Richienb, thanks for the fast response!! I may look into it later. @lifeiscontent, what do you think?

[lifeiscontent]

@Richienb I'd love to see an example, its hard to visualize as I don't have a full understanding of the ecosystem of rollup.

[Richienb]

The resolveId function in a rollup plugin is provided with the exact path within an import statement and the file that is importing it as arguments. We can use those arguments to generate a new path to be imported from.

[Richienb]

rollup/rollup#558

[sindresorhus]

You can solve this with the exports field in package.json, which is the modern way to expose subpaths.

[lifeiscontent]

@sindresorhus is this functionality that will work out of the box right now? or something that could be implemented in rollup as a potential feature?

[sindresorhus]

There's no need to use Rollup at all.

[Richienb]

Ohhhh, I misunderstood the question. I thought you wanted to remap imports from within the module itself on build time, like this rejected TypeScript request: microsoft/TypeScript#15479.

[papb]

Ahhh!! Awesome! Thank you all very much!!

@Richienb I was lucky that you misunderstood, because that TS issue you just linked happened to help me with something else here 😅