rxjs que recibe como parametro un observable

JavaScript
const $button = document.getElementById('main-button');const click$ = fromEvent($button, 'click');const subscription = click$.subscribe({  next: (e) => console.log('Event :', e)});// Luego de 5 segundos se cancela la suscripción a click$setTimeout(() => {  subscription.unsubscribe();}, 5000);import { Observable } from 'rxjs';const fromEvent = (node, name) => Observable.create((observer) => {  function handler(event) {    observer.next(event)  }  node.addEventListener(name, handler);  return () => {    node.removeEventListener(name, handler);  };});
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