50Implement a queue supporting pause, resume, and clear

Implement a TaskQueue class that runs async tasks in order with a concurrency limit, and can be paused, resumed and cleared.

• new TaskQueue({ concurrency = 1, autoStart = true }). With autoStart: false, the queue starts paused.
• add(task): returns a promise for the task's result.
• pause(): stop starting new tasks. Tasks already running continue.
• resume(): start running waiting tasks again.
• clear(): remove every waiting task. Their promises reject with an error whose name is "AbortError". Running tasks are not affected.
• size (waiting), pending (running) and isPaused.
• onIdle(): resolves when nothing is running and nothing is waiting.

const uploads = new TaskQueue({ concurrency: 2 });
files.forEach((file) => uploads.add(() => upload(file)));
offlineButton.onclick = () => uploads.pause();
onlineButton.onclick = () => uploads.resume();
cancelAllButton.onclick = () => uploads.clear();

Requirements

• Tasks start in the order they were added.
• pause() and resume() can be called any number of times in any order.
• A failing task rejects only its own promise.