Need help getting workers (worker_threads) to run in packaged app. Electron-Vite (Electron-Vite 1.0.29)

[stuartambient]

I have a few workers using the ?nodeWorker constructor. They run correctly in development. I use this code to start the worker -

import createUpdateTagsWorker from './updateTagsWorker?nodeWorker';
import createUpdateFilesWorker from './updateFilesWorker?nodeWorker';

const runWorker = (createWorkerFn, msg) => {
  return new Promise((resolve, reject) => {
    const worker = createWorkerFn(msg);

    // Handle messages from the worker
    worker.on('message', (result) => {
      console.log('Result, result);
      if (result.error) {
        reject(new Error(result.error));
      } else {
        resolve(result);
      }
    });

    // Handle errors from the worker
    worker.on('error', (err) => {
      console.error('Worker error:', err);
      reject(err);
    });

    // Handle worker exit
    worker.on('exit', (code) => {
      if (code !== 0) {
        const errorMessage = `Worker stopped with exit code ${code}`;
        console.error(errorMessage);
        reject(new Error(errorMessage));
      }
    });

    // Start the worker
    worker.postMessage(msg);
  });
};

export default runWorker;

All the worker files sit in src/main but after build (for Windows) I get this error:

MODULE_NOT_FOUND 
requireStack: Array(2), name: 'Error', message: "Cannot find module 'electron'\nRequire stack:\n- C:\\…s\\app.asar\\out\\main\\updateFilesWorker.b4a10f6f.js
code "MODULE_NOT_FOUND".....

What am I not doing right ? Do I need to reference them somewhere (electron.vite.config) or do something in my builder.yml ? Moving Electron from devDependencies to dependencies not allowed though I doubt that is the actual issue.

Help appreciated.