使用wxs，写在wxml最上边

<wxs module=“test”>

    sum = 0

    T = {

        add : function(n){

            sum += parseFloat(n)

        },

        getSum : function(){

            a = sum

            sum = 0

            return a == 0 ? ‘0.00’ : a

        }

    }

    module.exports = T

</wxs>

使用

<view wx:for="{{two.tranGroupDet}}" wx:for-item=“three” wx:key=“id”>

    {{test.add(three.discountAmount)}}

    <view class=“table shuye”>

        …

    </view>

    <view wx:if="{{index+1==two.tranGroupDet.length}}">合计:{{test.getSum()}}</view>

</view>