source: trip-planner-front/node_modules/rxjs/src/internal/scheduler/QueueAction.ts

import { AsyncAction } from './AsyncAction';
import { Subscription } from '../Subscription';
import { QueueScheduler } from './QueueScheduler';
import { SchedulerAction } from '../types';

/**
 * We need this JSDoc comment for affecting ESDoc.
 * @ignore
 * @extends {Ignored}
 */
export class QueueAction<T> extends AsyncAction<T> {

  constructor(protected scheduler: QueueScheduler,
              protected work: (this: SchedulerAction<T>, state?: T) => void) {
    super(scheduler, work);
  }

  public schedule(state?: T, delay: number = 0): Subscription {
    if (delay > 0) {
      return super.schedule(state, delay);
    }
    this.delay = delay;
    this.state = state;
    this.scheduler.flush(this);
    return this;
  }

  public execute(state: T, delay: number): any {
    return (delay > 0 || this.closed) ?
      super.execute(state, delay) :
      this._execute(state, delay) ;
  }

  protected requestAsyncId(scheduler: QueueScheduler, id?: any, delay: number = 0): any {
    // If delay exists and is greater than 0, or if the delay is null (the
    // action wasn't rescheduled) but was originally scheduled as an async
    // action, then recycle as an async action.
    if ((delay !== null && delay > 0) || (delay === null && this.delay > 0)) {
      return super.requestAsyncId(scheduler, id, delay);
    }
    // Otherwise flush the scheduler starting with this action.
    return scheduler.flush(this);
  }
}