自定义指令实现拷贝功能

import Vue from 'vue'
import store from '../store'

function copyMethod(value) {
 let text = ''
 switch (typeof value) {
  case 'number':
   text = value.toString()
   break
  case 'object':
   text = JSON.stringify(value)
   break
  default:
   text = value
   break
 }
 let input = document.createElement('textarea')
 input.value = text
 document.body.appendChild(input)
 input.select()
 document.execCommand('copy')
 store.commit('success_msg', '复制成功')
 document.body.removeChild(input)
 input = null
}

Vue.directive('copy', {
 bind(el, binding) {
  el.handler = () => copyMethod(binding.value)
  el.addEventListener('click', el.handler)
 },
 // 更新参数时更新监听函数
 componentUpdated(el, binding) {
  el.removeEventListener('click', el.handler)
  el.handler = () => copyMethod(binding.value)
  el.addEventListener('click', el.handler)
 },
 unbind(el) {
  el.removeEventListener('click', el.handler)
  el.handler = null
 },
})