POST /trade/v1/payment

{
  "user_creid": "430067798868676871",
  "user_truename": "\\u5c0f\\u6797"
}

qfPayOpenAPI: function () {
  let app_code = '******';
  let client_key = '******';
  let environment = 'https://test-openapi-hk.qfapi.com/trade/v1/payment';

  let payload = {
    txamt: 100,
    txcurrcd: 'SGD',
    pay_type: '800213',
    out_trade_no: '0123456789',
    txdtm: '2020-07-03 03:14:29',
    sub_openid: 'oS80_5dxekECAOlVBeQFk34q123s'
  };

  var ordered = {};
  Object.keys(payload).sort().forEach(function(key) {
    ordered[key] = payload[key];
  });

  var str = [];
  for (var p in ordered) {
    str.push(p + "=" + ordered[p]);
  }

  var signature = utilMd5.hexMD5(str.join("&") + client_key).toUpperCase();

  wx.request({
    url: environment,
    data: payload,
    method: 'POST',
    header: {
      'X-QF-APPCODE': app_code,
      'X-QF-SIGN': signature,
      'content-Type': 'application/x-www-form-urlencoded'
    },
    success: (res) => {
      if (res.statusCode == 200) {
        this.weChatPayment(res);
      }
    }
  })
}

weChatPayment: function(res) {
  wx.requestPayment({
    timeStamp: res.data.pay_params.timeStamp,
    nonceStr: res.data.pay_params.nonceStr,
    package: res.data.pay_params.package,
    signType: res.data.pay_params.signType,
    paySign: res.data.pay_params.paySign,
    success: function(res){},
    fail: function(res){},
    complete: function(res){}
  })
}

https://test-openapi-hk.qfapi.com