统一下单接口返回值如下：

{

 "data":{

  "appid":"xxxxxxxxxxxxx",

  "code_url":null,

  "device_info":null,

  "err_code":null,

  "err_code_des":null,

  "mch_id":"xxxxxxxxx",

  "nonce_str":"K9fbnZApE2er9PlG",

  "prepay_id":"wx2811265848135443f070fcd053199e0000",

  "result_code":"SUCCESS",

  "return_code":"SUCCESS",

  "return_msg":"OK",

  "sign":"xxxxxC4E12955DE3251E57D00Fxxxxx",

  "trade_type":"JSAPI"

 },

 "extra":null,

 "msg":"操作成功",

 "path":"/api/wxpay/wxpay/JsApi",

 "status":200,

 "success":true,

 "timestamp":1611804418518

}

小程序请求如下：

返回：errMsg: "requestPayment:fail cancel 签名失败