queuescheduler.md

QueueScheduler class

This is much like the SyncScheduler but maintains a PriorityQueue underneath for keeping items in order for recursive or re-entrant scheduling. This is useful for operations that can be done synchronously. This should be used instead of the SyncScheduler for recursive scheduling as it has a trampoline feature which allows for greater depths of recursive actions. Future work scheduling using this scheduler is not permitted. This class inherits from the Scheduler class.

Usage

To show the differences between the QueueScheduler and SyncScheduler, here is a little mechanism to show how the items are queued using the QueueScheduler versus the SyncScheduler which executes immediately.

'use strict';

const SyncScheduler = require('rx.schedulers').SyncScheduler;
const QueueScheduler = require('rx.schedulers').QueueScheduler;

const syncScheduler = new SyncScheduler();
const queueScheduler = new QueueScheduler();

syncScheduler.schedule(42, (scheduler, state) => {
  scheduler.schedule(43, (scheduler, state) => {
    console.log(state);
  });

  console.log(state);
});

// => 43
// => 42

queueScheduler.schedule(84, (scheduler, state) => {
  scheduler.schedule(85, (scheduler, state) => {
    console.log(state);
  });

  console.log(state);
});

// => 84
// => 85