<block wx:for="{{catalogData}}" wx:key="id" wx:for-item="item" class="item">
  <view class="scroll-view-item catalog-title {{curIndex == index " data-index="{{index}}" catchtap="goIndex">{{item.catalog}}</view>
</block>

Component({
 /**
  * 组件的属性列表
  */
 properties: {
  catalogData:{
   type: Array,
  }
 },
 /**
  * 组件的初始数据
  */
 data: {
   curIndex:0
 },  
  /**
   * 组件的方法列表
   */
  methods: {
    goIndex(event) {
      let nextIndex = event.currentTarget.dataset.index;
      this.setData({
        curIndex: nextIndex
      })      
      console.log(this.data.curIndex + '=' + nextIndex);
    },
  }
})