esm typings are weak or I have done something wrong

[kirevdokimov]

TLDR

Types from npm run build-dts and esm build from npm run build-esm don't work together

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Problem

Plain project, no bundlers, just Typescript 3.9.6 with "es6" target to compile.

I was going to use gl-matrix as a bundled dependency because of no bundler. I got esm dist from npm run build-esm then copy to my ./src/esm dir. Works just fine, but no types (like mat4.create() returns any instead of mat4 so I can't handle it with Typescript)

So I have made index.d.ts from npm run build-dts. Keeping this in root folder provides no types, for this reason I just copied this right to ./src/esm. But now I got

src/Cube.ts:7:22 - error TS2306: File '/mnt/c/Project/subtract-n-triangulate/src/esm/index.d.ts' is not a module.

7 import { mat4 } from "./esm/index.js";
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Found 1 error.

For sure I can not an expert in typescript module declarations, but something looks wrong with all this. Would be happy to get some advice or solution. Thank you.

[kirevdokimov]

Ok, got it.

First of all we declare our wrap module but never export it from index.d.ts:

gl-matrix/utils/bundle-dts.js

Lines 37 to 38 in fccd5f7

	// Wrap them in a "gl-matrix module"
	typings = 'declare module "gl-matrix" {\n' + typings + "\n}";

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gl-matrix/utils/bundle-dts.js

Line 10 in fccd5f7

// Honestly, this is just a horrible hack.

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Second, even if we replace declare with export we still don't have types, because of module "gl-matrix" wrap. There is probably a reason for this to be here, but if I remove it, everything works just as I initially expect.