how to use the fromevent function from the rxjs library in javascript

The fromEvent function in rxjs library can be used to create an observable stream of events from a DOM element or node.js EventEmitter.

Here is an example of how to use fromEvent to listen for a 'click' event on a button element:

index.tsx
import { fromEvent } from 'rxjs';

const button = document.querySelector('button');
const click$ = fromEvent(button, 'click');

click$.subscribe(event => {
  console.log('Button clicked!', event);
});
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In the above code, we import the fromEvent function from the rxjs library. We select a button element from the DOM and pass it along with the event type 'click' to fromEvent. This returns an observable stream of 'click' events on the button.

We then subscribe to this stream with a callback function that logs the event object to the console whenever the button is clicked.

Similar to 'click', we can use any other standard DOM event type (like 'mousemove', 'keydown', etc.) or any custom event type emitted by a node.js EventEmitter, with the fromEvent function.