<div class="cover" @click="close">
 <!-- 阻止冒泡 -->
 <div class="content" @click.stop>modal content</div>
</div>

<div class="cover" @click="handleClick">
 <div class="content" ref="content">modal content</div>
</div>
handleClick (e) {
 let clickOut = true
 let temp = e.target
 do {
  if (temp === this.$refs.content) {
   clickOut = false
   break
  }
  temp = temp.parentElement
 } while (temp !== document.documentElement)
 console.log(clickOut)
}

<div class="cover">
 <div class="content" v-out-click="close">modal content</div>
</div>

<button @click="popIsShow = true">显示气泡</button>
<div class="pop" v-if="popIsShow" v-out-click="closePop">I'm pop text</div>

import outClick from './directive/out-click.js'
Vue.directive(outClick.name, outClick)
const KEY_OUT = '_out_click'
const KEY_OUT_EVENT = '_out_click_event'
const KEY_IN = '_in_click'
const KEY_FLAG = '_in_out_flag'

function removeEvent(el, binding, vnode) {
 el.removeEventListener('click', el[KEY_IN], false)
 window.removeEventListener('click', el[KEY_OUT], false)
 delete el[KEY_IN]
 delete el[KEY_OUT]
 delete el[KEY_OUT_EVENT]
 delete el[KEY_FLAG]
}

function initEvent(el, binding, vnode) {
 // setTimeout 0: 忽略点击外部的按钮初始化该组件时，触发的origin click
 setTimeout(() => {
  el[KEY_OUT] = () => outClick(el)
  el[KEY_IN] = () => inClick(el)
  el[KEY_OUT_EVENT] = binding.value
  el.addEventListener('click', el[KEY_IN], false)
  window.addEventListener('click', el[KEY_OUT], false)
 }, 0)
}

function inClick(el) {
 // 通过事件捕获的顺序作为标志位
 // 最好不要使用阻止冒泡来实现，那样会影响其他的click无法触发
 el[KEY_FLAG] = '1'
}

function outClick(el) {
 if (!el[KEY_FLAG] && el[KEY_OUT_EVENT]) {
  el[KEY_OUT_EVENT]()
 }
 delete el[KEY_FLAG]
}

export default {
 name: 'out-click',
 update: (el, binding, vnode) => {
  if (binding.value === binding.oldValue) {
   return
  }
  removeEvent(el, binding, vnode)
  initEvent(el, binding, vnode)
 },
 bind: initEvent,
 unbind: removeEvent
}