debounce还是throttle(去抖和节流)

debounce 去抖

我的理解很简单，比方说window.onscroll会疯狂触发handler，此时给它一个debounce(handler, delayTime).
就是不管你延时时间内触发了多少hanlder，我最后只执行一次。（理解把之前多次触发合并成一次，节省浏览器工作）

function debounce(fn, delay) {
  var ctx
  var args
  var timer = null
  var later = function () {
    fn.apply(ctx, args)
    timer = null
  }
  return function () {
    ctx = this
    args = arguments
    if (timer) {
      clearTimeout(timer)
      timer = null
    }
    timer = setTimeout(later, delay)
  }
}

throttle 节流

不管你怎么触发#24，反正我就是固定时间内必定触发一次

function throttle(fn, delay) {
  var ctx
  var args
  var previous = Date.now()
  var later = function () {
    fn.apply(ctx, args)
  }
  return function () {
    ctx = this
    args = arguments
    var now = Date.now()
    var diff = now - previous - delay
    if (diff >= 0) {
      previous = now
      setTimeout(later, delay)
    }
  }
}

以上参考地址：https://segmentfault.com/a/1190000005926579
我在想 throttle可以这样改吗。。。

function throttle(fn, delay) {
  var ctx
  var args
  var timer = null
  var later = function () {
    fn.apply(ctx, args)
    timer = null
  }
  return function () {
    ctx = this
    args = arguments
    if (timer) return
    timer = setTimeout(later, delay)
  }
}

哈哈这段我没测试鸭（懒癌）。错了请告诉我我删掉