rxjs/operators#scan JavaScript Examples

The following examples show how to use rxjs/operators#scan. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example #1
Source File: date-keeper.js    From real-time-map with MIT License 4 votes vote down vote up 
dateKeeper = {

  init(startDate, period = 1000) {

    this.startDate = startDate;
    this.newTime = startDate;
    this.period = period;
    this.paused = false;

    this.emitterSubject = new Subject();
    this.inputThrottler = new Subject();

    this.currentSecond$ = this.createDateKeeper();
    this.createInputThrottler();

    this.subscriberList = [];
  },

  get state() {
    // console.trace(new Date(this.newTime));
    return {
      period: this.period,
      newTimeSet: this.newTime,
      pause: this.paused
    };
  },

  get observable() {
    return this.currentSecond$;
  },

  getPeriod() {
    return this.period;
  },

  createDateKeeper() {
    const res = this.emitterSubject.pipe(

      startWith(this.state),

      switchMap(next => {

        if (next.pause) {
          return empty();
        }

        const res = interval(next.period).pipe(mapTo(false));
        if (next.newTimeSet) {
          this.newTime = false;
          return res.pipe(startWith(next.newTimeSet));
        }
        return res;

      }),

      scan((currentTime, newTimeSet) =>
        newTimeSet ? newTimeSet : currentTime + 1000,
        0
      ),

      publish()
    );

    res.connect();
    this.newTime = false;
    return res;
  },

  createInputThrottler() {

    this.inputThrottler.pipe(
      throttleTime(360)
    ).subscribe(state => {
      this.emitterSubject.next(state);
    });

  },

  emitNext() {
    this.inputThrottler.next(this.state);
  },

  subscribe(callback) {
    const newSub = this.currentSecond$.subscribe(callback);
    this.subscriberList.push(newSub);
    return newSub;
  },

  pause() {
    this.paused = true;
    this.emitNext();
  },

  resume() {
    this.paused = false;
    this.emitNext();
  },

  setPeriod(period) {
    this.period = period;
    this.paused = false;
    updatePeriodChangeFunctions(period);
    this.emitNext();
  },

  setNewTime(newTimeInput) {

    this.newTime = Math.round(newTimeInput / 1000) * 1000;

    if (this.newTime < storage.dayStart.getTime() || this.newTime > storage.dayEnd.getTime()) {
      this.pause();
      differentDateSet(this.newTime);
    }

    if (checkIfLive(this.newTime) > 600) {
      this.newTime = getLiveTime();
    }

    storage.currentTime = this.newTime;
    updateTimeChangeFunctions(this.newTime);

    this.paused = false;
    this.emitNext();
    resetTransitionAnimation();
  },

  update() {

    storage.currentTime += 1000;

    if (checkIfLive(storage.currentTime) > 600) {
      storage.currentTime = getLiveTime();
    }

    this.setNewTime(storage.currentTime);
  }

}