How to feed an rxjs observer

Question

everyone seems to find observers easy but i find them extremely difficult. I need to create an observable then feed a number to it when a button is pressed, in all the examples that i found they define the content of the observable in the constructor but i need to feed it after is created. Is this even possible?

Thanks

Answer 1

 const { Subject, fromEvent } = rxjs; const number$ = new Subject(); fromEvent(document.getElementById('button'), 'click').subscribe(() => { number$.next(Math.random() * 10); }); number$.subscribe(number => { document.getElementById('output').innerText = number; }); 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/rxjs/6.3.3/rxjs.umd.min.js"></script> <button id="button">Click for random number</button> <div id="output"></div>