How to Prevent a Node.js 12 worker Thread from terminating immediately?

I'm mostly spitballin' here, but I think this'll put you on the right track:

add to start.js

process.on('SIGTERM', cleanup);
process.on('SIGINT', cleanup);
myWorker.once('exit', stop);

function cleanup() {
  myWorker.postMessage('cleanup');
}

worker.js

const { parentPort } = require('worker_threads');

parentPort.on('message', (value) => {
  if (value === 'cleanup') {
    cleanup();
    //then process.exit(0);
  }
});

The following solution should work-

• Subscribe to main thread message event in the worker thread
• Subscribe to SIGTERM (or whatever) in the main thread
• When you catch the signal in the main thread, send a message to the worker thread, requesting it to clean up and exit. ** Do not exit from the main thread yet**.
• In the main thread wait for worker thread to stop by subscribing to exit event.
• When worker thread stops, exit from the main thread.