Method push

src/util/blocking-queue.js:64–80

(key: string, factory: () => Promise<T>)

  }

  push<T>(key: string, factory: () => Promise<T>): Promise<T> {
    if (this.first) {
      this.first = false;
    } else {
      this.stillActive();
    }

    return new Promise((resolve, reject) => {
      // we're already running so push ourselves to the queue
      const queue = (this.queue[key] = this.queue[key] || []);
      queue.push({factory, resolve, reject});

      if (!this.running[key]) {
        this.shift(key);
      }
    });
  }

  shift(key: string) {
    if (this.running[key]) {