AsyncQueue.ts

AsyncQueue.ts

class AsyncQueue<T> {
  #elements: T[] = [];
  #waiting: ((el: T) => void)[] = [];
  get size() { return this.#elements.length }

  enqueue(el: T) {
    const next = this.#waiting.shift();
    if (next) {
      next(el);
    } else {
      this.#elements.push(el);
    }
  }
  async dequeue() {
    const next = this.#elements.shift();
    if (next) {
      return next;
    } else {
      const defer = new Promise<T>(res => this.#waiting.push(res))
      return defer;
    }
  }
}