wamr-93.ts

import { Observable } from 'rxjs';

const observable = new Observable<number>(observer => {
  let x = 0;

  const interval = setInterval(() => {
    if (x === 5) {
      observer.error('Oops');
    }
    else {
      observer.next(x++);
    }
  }, 1000);

  return {
    unsubscribe: () => clearInterval(interval)
  }
});

observable.subscribe(x => console.log(`${x} received`));