Why are interface declarations removed?

Hi,

I’m trying to move from webpack to rollup for a library and I have trouble getting declarations to work correctly.

It seems that interfaces declarations aren’t exported, this is a problem when I have things like :

import { RenderedCell } from "../RenderedCell";

export default class MergedCell implements RenderedCell {
    // ...
}

I get the error that RenderedCell can’t be found. I worked in webpack, and I can’t understand what’s the difference in my configuration that broke this. but I seem to understand that it’s normal with Rollup.

BTW. I’m using the latest rollup, rollup-plugin-typescript2 and rollup-plugin-uglify I can post my configurations if needed

[yiochen]

For what it’s worth, I just call tsc --emitDeclarationOnly after rollup, which overrides the declaration files into build folder. in my package.json

"scripts": {
    "build": "rollup -c",
    "postbuild": "tsc --emitDeclarationOnly"
}

[ezolenko]

Yep, just checked, adding import "./SomeInterface"; in the test repo fixes things.

When importing types only, typescript elides import statements from js output and rollup doesn’t see those files and thus doesn’t send them for transpiling.

I’ll try to cheat and monitor which files typescript requested from disk vs which files rollup sent for transpiling. Should be possible to force-transpile the difference with definitions only flag. This might result in too many d.ts files in some cases I though (for things rollup has legitimately shaken from the tree for example)