add：下单计算优惠接口

src/pages/cart/cart.js

@@ -224,21 +224,27 @@ wxService.page({
       return false
     }
     // 去下单页
-    // wxService
-    //   .router('/pages/confirmOrder/confirmOrder')
-    //   .search(parmas)
-    this.handleGoBuy(skuIds)
+    let parmas = {
+      specId: skuIds.join(',')
+    }
+  
+    wxService
+      .router('/pages/confirmOrder/confirmOrder')
+      .search(parmas)
+    // this.handleGoBuy(skuIds)
   },
   handleGoBuy(parmas) {
     // 下单
     wx.showLoading({
       title: '加载中'
     })
+    // 获取支付参数
     wxService.post(`/sale/trade/buyer/create`,parmas).then(res => {
       if (!res) return false;
       const { result, data } = res && res.data || res && res.result
       if (result == 0) {
         delete data.appId
+        console.log('data', data)
         wx.requestPayment(Object.assign({
           success(res) {
             wx.hideLoading()

src/pages/confirmOrder/confirmOrder.js

 // pages/confirmOrder/confirmOrder.js
-Page({
+const wxService = require('../../utils/wxService')
 
+wxService.page({
   /**
    * 页面的初始数据
    */
   data: {
     addressInfo: '',
-    showSelectCoupon: false
+    showSelectCoupon: false,
+    skuIds: []
   },
 
   /**
@@ -15,16 +17,29 @@ Page({
   onLoad: function (options) {
 
   },
-
-
-
   /**
    * 生命周期函数--监听页面显示
    */
   onShow: function () {
-
+    let skuIds = []
+    skuIds.push(this.options.specId)
+    // 计算优惠价
+    if(skuIds){this.calPreferentialPrice(skuIds)}
+  },
+  calPreferentialPrice(skuIds) {
+    wx.showLoading({
+      title: '加载中'
+    })
+    wxService.post(`/sale/trade/buyer/preview`,skuIds).then(res => {
+      if (res) {
+        const { result, data } = res.data
+        if (result == 0) {
+          wx.hideLoading()
+          console.log('data', data)
+        }
+      }
+    })
   },
-
   //获取微信地址
   chooseWxAddress() {
     wx.chooseAddress({