[RXJS] takUntil

/*
  Including https://unpkg.com/@reactivex/[email protected]/dist/global/rxjs.umd.js
  in index.html's script tag gives us rxjs globally available under window.rxj
*/
const { Observable } = rxjs
const { tap, map, first, takeUntil } = rxjs.operators

const observable$ = Observable.create((observer) => {
  observer.next(1)
  observer.next(2)
  observer.next(3)
  setTimeout(() => {
    observer.next(4)
    observer.complete()
  }, 4000)
})

const observableTakeUntil$ = Observable.create((observer) => {
  setTimeout(() => {
    observer.next()
    observer.complete()
  }, 2000)
})

observable$
  .pipe(
    map(data => data * 10),
    takeUntil(observableTakeUntil$)
  )
  .subscribe((data) => {
    console.log(data) // 1, 2, 3, 4
  })