3. Vue自定义全局指令-时间格式化案例

• 服务器一般会给返回时间戳，一般是10位，代表单位是秒钟。或13位，代表单位是毫秒

实现效果： 

1. App.vue 

<template>
  <div class="app">
    <h2 v-ftime>{
   
   { timetamp }}</h2>
    <h2 v-ftime="'YYYY-MM-DD'">{
   
   { 1230098765678 }}</h2>
    <h2 v-ftime>{
   
   { timetamp }}</h2>
  </div>
</template>

<script setup>

const timetamp = 1231231230

</script>

<style scoped></style>

2. 自定义指令 v-ftime

• 新建 directives/ ftime.js
• 下载 npm i day.js

import dayjs from 'dayjs'

export default function directiveFtime(app) {
  app.directive('ftime', {
    mounted(el, bindings) {
      // 1.获取时间，并转化成毫秒
      let timestamp = el.textContent
      console.log(timestamp) // 1231231230
      if (timestamp.length === 10) {
        // 这里有 * 可以隐式转换成数字型
        timestamp = timestamp * 1000
      }

      // 因为如果timestamp是 13位数的话，是字符串类型，这里需要转成数字型
      timestamp = Number(timestamp)
      // console.log(timestamp) // 1231231230000

      // 2.获取传入的参数
      let value = bindings.value
      if (!value) {
        value = 'YYYY-MM-DD HH:mm:ss'
      }
      // 2.对时间进行格式化
      const formatTime = dayjs(timestamp).format(value)
      el.textContent = formatTime
    }
  })
}

3.directives/index.js

import directiveFtime from './ftime'

export default function useDirectives(app) {
  directiveFtime(app)
}

4.main.js

import { createApp } from 'vue'
import App from './01_自定义指令/App.vue'
import useDirectives from './01_自定义指令/directives/index'

const app = createApp(App)
// 自定义指令
useDirectives(app)
app.mount('#app')