worker_execution_script.js

const publicWorker = require('worker_threads');

// ...redacted...

port.on('message', (message) => {
  if (message.type === 'loadScript') {
    const {
      cwdCounter,
      filename,
      doEval,
      workerData,
      publicPort,
      manifestSrc,
      manifestURL,
      hasStdin
    } = message;

    // ...redacted...
    initializeCJSLoader();
    initializeESMLoader();
    
    publicWorker.parentPort = publicPort;
    publicWorker.workerData = workerData;

    // ...redacted...
    
    port.unref();
    port.postMessage({ type: UP_AND_RUNNING });
    if (doEval) {
      const { evalScript } = require('internal/process/execution');
      evalScript('[worker eval]', filename);
    } else {
      process.argv[1] = filename; // script filename
      require('module').runMain();
    }
  }
  // ...redacted...