rxjs/src/internal/scheduled/scheduleArray.ts

Reactive Extensions for modern JavaScript

import { Observable } from '../Observable';
import { SchedulerLike } from '../types';

export function scheduleArray<T>(input: ArrayLike<T>, scheduler: SchedulerLike) {
  return new Observable<T>((subscriber) => {
    // The current array index.
    let i = 0;
    // Start iterating over the array like on a schedule.
    return scheduler.schedule(function () {
      if (i === input.length) {
        // If we have hit the end of the array like in the
        // previous job, we can complete.
        subscriber.complete();
      } else {
        // Otherwise let's next the value at the current index,
        // then increment our index.
        subscriber.next(input[i++]);
        // If the last emission didn't cause us to close the subscriber
        // (via take or some side effect), reschedule the job and we'll
        // make another pass.
        if (!subscriber.closed) {
          this.schedule();
        }
      }
    });
  });
}