Worker script missing from assets?

[rybesh]

I am creating a Vite app which depends on a library (@allmaps/render) that uses a Web Worker.

Allmaps also uses Vite to build their library, but there seems to be something wrong with the Vite bundling of the worker script causing it not to work—this is what I am trying to troubleshoot.

The TS source of the library initializes the Web Worker like this:

const worker = new Worker(
  new URL('../workers/fetch-and-get-image-data.ts', import.meta.url)
)

In the transpiled JS code of my Vite app I can see that this becomes:

const worker = new Worker(
      new URL(
        /* @vite-ignore */
        "" + new URL("/node_modules/.vite/assets/fetch-and-get-image-data-BXcOBitk.js", import.meta.url).href,
        import.meta.url
      )
    );

… which is promising because in the @allmaps/render npm package there is dist/assets/fetch-and-get-image-data-BXcOBitk.js.

But Vite does not seem to include this worker script in my app bundle; there is no node_modules/.vite/assets dir. When I try to curl http://localhost:5173/node_modules/.vite/assets/fetch-and-get-image-data-BXcOBitk.js I get back index.html (I guess as a fallback?), not the worker script. This is obviously causing the worker to fail (Uncaught SyntaxError: Unexpected token '<' (at fetch-and-get-image-data-BXcOBitk.js:1:1)).

Is this an Allmaps package publishing issue, or a Vite usage issue on my part? How can Vite be forced to include the worker script as an asset in the bundle?

[rybesh]

I’ve confirmed that if I simply

mkdir -p node_modules/.vite/assets
cp node_modules/@allmaps/render/dist/assets/* node_modules/.vite/assets/

… before I run the Vite dev server, everything works as expected.

And, even better, the production build works as-is. So, this only seems to be a problem with the dev server, and is easily fixed by manually copying the worker script into assets/.