SOURCE

new Vue({
  el: '#demo',
  data: {
    show: true,
    list:[1]
  }
})

<div id="demo">
  <button v-on:click="list.push(+new Date())">
    添加
  </button>
    <button v-on:click="list.pop()">
    移除
  </button>
  <transition-group tag="ul" >
    <li v-for="item of list" :key="item">hellohellohellohellohellohellohelloh
        ellohellohellohellohellohellohellohellohellohell
        ohellohellohello</li>
  </transition-group>
</div>

.v-enter-active{
transition: all 1s;
}
 .v-leave-active {
transition: all 1s;
}
.v-enter, .v-leave-to /* .fade-leave-active below version 2.1.8 */ {
  opacity: 0;
  transform: translateX(100px);
}


.v-item {
  display: inline-block;
  margin-right: 10px;
}

@keyframes bounce-in {
  0% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(-500px);
  }
}