使用vue-router切换页面时实现设置过渡动画

import VueRouter from 'vue-router'
import Home from '../components/home/home'
import User from '../components/user/user'

var router = new VueRouter({
  routes:[{
    name:'test',
    path:'/',
    meta:{index:0},//meta对象的index用来定义当前路由的层级,由小到大,由低到高
    component:{
      template:'<div>test</div>'
    }
  },{
    name:'home',
    path:'/home',
    meta:{index:1},
    component:Home
  },{
    name:'user',
    path:'/user/:id',
    meta:{index:2},
    component:User
  }]
});

<template>
 <div id="app">
  <transition :name="transitionName">  
   <router-view></router-view>
  </transition>
 </div>
</template>

<script>
export default {
 name: 'App',
 data(){
   return {
     transitionName:''
   }
 },
 watch: {//使用watch 监听$router的变化
  $route(to, from) {
   //如果to索引大于from索引,判断为前进状态,反之则为后退状态
   if(to.meta.index > from.meta.index){
   //设置动画名称
    this.transitionName = 'slide-left';
   }else{
    this.transitionName = 'slide-right';
   }
  }
 }
}
</script>

.slide-right-enter-active,
.slide-right-leave-active,
.slide-left-enter-active,
.slide-left-leave-active {
 will-change: transform;
 transition: all 500ms;
 position: absolute;
}
.slide-right-enter {
 opacity: 0;
 transform: translate3d(-100%, 0, 0);
}
.slide-right-leave-active {
 opacity: 0;
 transform: translate3d(100%, 0, 0);
}
.slide-left-enter {
 opacity: 0;
 transform: translate3d(100%, 0, 0);
}
.slide-left-leave-active {
 opacity: 0;
 transform: translate3d(-100%, 0, 0);
}