element-ui中的clickoutside点击空白隐藏元素

2023-03-06 11:11

短信预约 -IT技能 免费直播动态提醒

前言

大家好，今天主要比较简单的了解下clickoutside指令的作用，主要作用是自己手动实现类似下拉的组件，想要点击空白隐藏下拉框，可以使用该指令，看下element-ui怎么实现的。

基本使用

点击div，closeBox方法不会执行，点击空白才执行

<template>
  <div class="app">
    <div v-show="isShowBox" v-clickoutside="closeBox" class="box"></div>
  </div>
</template>
<script>
import Clickoutside from 'element-ui/class="lazy" data-src/utils/clickoutside'
export default {
  directives: {
    Clickoutside
  },
  data() {
    return {
      isShowBox: true
    }
  },
  methods: {
    closeBox() {
      this.isShowBox = false;
    }
  }
};

源码实现

在document元素上注册'mousedown'和'mouseup'事件,mouseup时会执行使用了该指令元素上的documentHandler方法
documentHandler方法里判断点击的元素是否为使用了指令的元素，不是就执行closeBox的方法

import Vue from 'vue';
import { on } from 'element-ui/class="lazy" data-src/utils/dom';
const nodeList = [];
const ctx = '@@clickoutsideContext';
let startClick;
let seed = 0;
on(document, 'mousedown', e => (startClick = e));
on(document, 'mouseup', e => {
  nodeList.forEach(node => node[ctx].documentHandler(e, startClick));
});
function createDocumentHandler(el, binding, vnode) {
  return function(mouseup = {}, mousedown = {}) {
    if (!vnode ||
      !vnode.context ||
      !mouseup.target ||
      !mousedown.target ||
      el.contains(mouseup.target) ||
      el.contains(mousedown.target) ||
      el === mouseup.target ||
      (vnode.context.popperElm &&
      (vnode.context.popperElm.contains(mouseup.target) ||
      vnode.context.popperElm.contains(mousedown.target)))) return;
    if (binding.expression &&
      el[ctx].methodName &&
      vnode.context[el[ctx].methodName]) {
      vnode.context[el[ctx].methodName]();
    } else {
      el[ctx].bindingFn && el[ctx].bindingFn();
    }
  };
}

export default {
  bind(el, binding, vnode) {
    nodeList.push(el);
    const id = seed++;
    el[ctx] = {
      id,
      documentHandler: createDocumentHandler(el, binding, vnode),
      methodName: binding.expression,
      bindingFn: binding.value
    };
  },
  update(el, binding, vnode) {
    el[ctx].documentHandler = createDocumentHandler(el, binding, vnode);
    el[ctx].methodName = binding.expression;
    el[ctx].bindingFn = binding.value;
  },
  unbind(el) {
    let len = nodeList.length;
    for (let i = 0; i < len; i++) {
      if (nodeList[i][ctx].id === el[ctx].id) {
        nodeList.splice(i, 1);
        break;
      }
    }
    delete el[ctx];
  }
};