Mini Programs use Mini Program Cloud to implement WeChat payment functions

const cloud = require('wx-server-sdk')
cloud.init({
  env: cloud.DYNAMIC_CURRENT_ENV
})

exports.main = async (event, context) => {    
const res = await cloud.cloudPay.unifiedOrder({
    "body" : event.body,
    "outTradeNo" : event.outTradeNo,
    "spbillCreateIp" : "127.0.0.1",
    "subMchId" : "0000000000", //Note here: although the key is the sub-merchant id, it is actually the normal merchant id
    "totalFee" : parseInt(event.totalFee), //Second pitfall: Note that it must be a number. If it is not a number, an error will be reported: unifiedOrder:fail wx api error: -202
    "envId": "ooo-xxxxxxxxxxxxxxxx", //This is the cloud environment id to which the callback function belongs
    "functionName": "payCallBack", //This is the callback function name"nonceStr":event.nonceStr, //The third pitfall: The relevant cloud function code in the official document does not have nonceStr and tradeType. When testing, it will report an error that nonceStr does not exist. I looked through the document and found that this is a required item. After pasting it directly, you need to add these two parameters"tradeType":"JSAPI"
  })
  return res
}

//Call cloud function, WeChat unified order cloudPay(){
    var _this = this
    this.setData({
      body: "Bill Payment-xxxxx",
      outTradeNo: this.data.id+"-"+util.uuid(16),
      totalFee: this.data.totalCost*100 //payment unit: cents})
    app.showLoading(true)
    wx.cloud.callFunction({
      name: "pay",
      data: {
        body: _this.data.body,
        outTradeNo: _this.data.outTradeNo,
        totalFee: _this.data.totalFee,
        nonceStr:util.uuid(32)//Call your own uuid function},
      success(res) {
        // errCode: 0
        // errMsg: "cloudPay.unifiedOrder:ok"
        // returnCode: "FAIL"
        // returnMsg: "total_fee is empty."
        console.log("Submission successful", res.result)
        if(res.result.returnCode!="SUCCESS"){
          app.showToast(res.result.returnMsg)
          return
        }
        _this.unifiedOrder(res.result)
        // _this.requestPayment(res.result)
      },
      fail(res) {
        console.log("Submission failed", res)
      }
    })
  },

  //Official standard payment method, call up the payment interface requestPayment(payData) {
    var _this = this;
    const payment = payData.payment //Note that the result of the previous function directly integrates the parameters to be used here. You can directly expand it and use wx.requestPayment({
      ...payment, //...is the syntax for expanding variables success(res) {
        console.log("Payment successful", res)
        _this.paySuccess()
      },
      fail(res) {
        console.log("Payment failed", res)
      }
    })
  },