微信小程序如何像vue一样在动态绑定类名

<wxs module="rank">
 var indexof = function(index){
 switch(index){
 case 0:
 return 'first-price';
 break;
 case 1: 
 return 'second-price';
 break;
 case 2: 
 return 'third-price';
 break;
 }
 };
 module.exports.style = indexof;
 </wxs>

 <view class="weui-badge {{rank.style(index)}}">{{index + 1}}</view>

 <div v-if="type === 'A'">
  A
 </div>
 <div v-else-if="type === 'B'">
  B
 </div>
 <div v-else-if="type === 'C'">
  C
 </div>
 <div v-else>
  Not A/B/C
 </div>

<view wx:if="{{length > 5}}"> 1 </view>
<view wx:elif="{{length > 2}}"> 2 </view>
<view wx:else> 3 </view>

VUE:v-show="..."

<div class="test" v-bind:class="{ active: isActive }"></div>

<view class="test {{isActive "></view>

<button v-on:click="counter += 1">Add 1</button>
<button v-on:click.stop="counter+=1">Add1</button> //阻止事件冒泡

<button bindtap="clickMe">点击我</button>
<button catchtap="clickMe">点击我</button> //阻止事件冒泡