A toy observables library inspired by RxJS, with pipeable operators.
https://steveholgado.com/understanding-observables
<input id="textbox" type="text" />
const textbox = document.querySelector('#textbox')
const obs$ = fromEvent(textbox, 'keyup')
.pipe(
filter(e => e.keyCode === 13), // "Enter" key
map(e => e.target.value)
)
const subscription = obs$.subscribe(v => console.log(v))
setTimeout(() => {
subscription.unsubscribe()
}, 5000)