setTimeout block execution code block in NativeEventEmitter callback

Question

I am trying to send a string to the native side (android) with a delay. But setTimeout is blocking the execution. Could you explain what is happening?

const eventEmitter = new NativeEventEmitter(Module);

const  waitFor = (delay) {   return new Promise((resolve) => setTimeout(resolve, delay)); }

const onFrameUpdate = async (e: string) => {
  // Ignore onFrameUpdate stream
  if (isPaused) {
    console.log('Js on Pause');
    return;
  }
  isPaused = true;
  console.log('Js working');

  if (e.hasOwnProperty('frameIndex')) {
    await Module.setLabelText(`Hello`) ; // -> this is set text on native side in UI
    await waitFor(1000);  //  remove this line and everything will be working fine, but I need a delay.
    await Module.setLabelText(`hello2`); // this text will never 
    isPaused = false;
  }
};

const onFrameUpdateSubscription = eventEmitter.addListener(  'onFrameUpdate',  onFrameUpdate );

Answer 1

In React Native setTimeout() will never working in background. It will be executed immediately after react native ui will become to front again.

I implement background timer setTimeout on objC and java side manually and it works as expected now.