// 防抖
export function debounce(fn, wait) {
  let timeout = null
  return function() {
    if (timeout !== null) {
      clearTimeout(timeout)
    }
    timeout = setTimeout(fn, wait)
  }
}
// 节流
export function throttle(fn, delay) {
  let valid = true
  return function() {
    if (!valid) {
      // 休息时间 暂不接客
      return false
    }
    // 工作时间，执行函数并且在间隔期内把状态位设为无效
    valid = false
    setTimeout(() => {
      fn()
      valid = true
    }, delay)
  }
}