class ScrollQueue {
  private resolve: (() => void) | null = null
  private promise: Promise<any> | null = null

  add() {
    this.promise = new Promise(resolve => {
      this.resolve = resolve
    })
  }

  flush() {
    this.resolve && this.resolve()
    this.resolve = null
    this.promise = null
  }

  async wait() {
    await this.promise
  }
}

export const scrollWaiter = new ScrollQueue()