Vue根据directive指令进行div拖拽，解决拖拽drag后触发点击click事件，并在directive中调用this

Vue根据directive指令进行div拖拽，解决拖拽drag后触发点击click事件，解决directive无法获取this的问题

开始做拖拽上网查了一些资料，拖拽效果容易做到，但是拖拽后会触发默认的点击事件，于是又上网搜索找到了方法，将click后的事件移入到directive中处理，然后发现无法获取到环境中的this，下面以拖拽button做为示例：
html

text

js

export default {
  directives: {
    drag(el,binding,vnode) {
      let clientOffset = {};
      el.onmousedown = function(e) {
        var disx = e.pageX - el.offsetLeft
        var disy = e.pageY - el.offsetTop
        clientOffset.clientX = event.clientX;
        clientOffset.clientY = event.clientY;
        document.onmousemove = function (e) {
          el.style.left = e.pageX - disx + 'px'
          el.style.top = e.pageY - disy + 'px'
        }
        document.onmouseup = function() {
          document.onmousemove = document.onmouseup = null
        }
      }
      el.addEventListener('mouseup', (event) => {     //鼠标抬起后的事件，判断是拖拽还是点击
      let clientX = event.clientX;
      let clientY = event.clientY;
      if (clientX === clientOffset.clientX && clientY === clientOffset.clientY) {        //这里触发点击事件，将click方法移入这里
      let that = vnode.context        //通过vnode参数来获取this,此时的that就可以获取到js中的this
      } else { 
        return     //这里是拖拽事件
      }
    })}
  },
}