ssj_book/templates/loading/loading.wxml

<!--templates/loading/loading.wxml-->
<template name='loading'>
  <view class='loading-box'>
    <image class='loading-box-item loading-box-item-{{~~index+1}}' wx:for='{{3}}' wx:key='index' src='../../../assets/loading_{{~~index+1}}.png'></image>
  </view>
</template>