catstodon/app/javascript/themes/glitch/util/schedule_idle_task.js

// Wrapper to call requestIdleCallback() to schedule low-priority work.
// See https://developer.mozilla.org/en-US/docs/Web/API/Background_Tasks_API
// for a good breakdown of the concepts behind this.

import Queue from 'tiny-queue';

const taskQueue = new Queue();
let runningRequestIdleCallback = false;

function runTasks(deadline) {
  while (taskQueue.length && deadline.timeRemaining() > 0) {
    taskQueue.shift()();
  }
  if (taskQueue.length) {
    requestIdleCallback(runTasks);
  } else {
    runningRequestIdleCallback = false;
  }
}

function scheduleIdleTask(task) {
  taskQueue.push(task);
  if (!runningRequestIdleCallback) {
    runningRequestIdleCallback = true;
    requestIdleCallback(runTasks);
  }
}

export default scheduleIdleTask;