Example for https://stackoverflow.com/questions/54922867/rxjs-takeuntil-do-not-execute-finalize

index.js

const { rxObserver } = require('api/v0.3');
const { timer, Subject } = require('rxjs');
const { tap, take, takeUntil, map } = require('rxjs/operators');

const userClick = new Subject();
let counter = 5;
let tick = 10;

    timer(0, tick)
      .pipe(
        take(counter + 1),
        map(value => counter - value),
        tap(value => {
          if (value === 0) {
            console.log('OUT OF TIME');
          }
        }),
        takeUntil(userClick)
      )
  .subscribe(rxObserver('timer(10)'));

// setTimeout(()=>{
//   userClick.next(void 0);
// }, 30);