wx.requestPayment({
  timeStamp: '',
  nonceStr: '',
  package: '',
  signType: 'MD5',
  paySign: '',
  success (res) { },
  fail (res) { }
})

npm i wechatpay-node-v3

const WxPay = require('wechatpay-node-v3');
const fs = require('fs');
const request = require('superagent');
const express = require('express');

const pay = new WxPay({
  appid: '你的微信小程序appid',
  mchid: '商戶號(hào)',
  publicKey: fs.readFileSync('./apiclient_cert.pem'), // 公鑰
  privateKey: fs.readFileSync('./apiclient_key.pem'), // 秘鑰
});

async function payInfo(req,res){
	const params = {
        description: 'Asnull的支付測(cè)試', // 訂單描述
        out_trade_no: '2022080711111111', // 訂單號(hào)，一般每次發(fā)起支付都要不一樣，可使用隨機(jī)數(shù)生成
        notify_url: 'https://pay.lipux.cn/notify_url', 
        amount: {
          total: 1, // 支付金額，單位為分
        },
        payer: {
          openid: 'drEc8QfY', // 微信小程序用戶的openid，一般需要前端發(fā)送過(guò)來(lái)
        },
        scene_info: {
          payer_client_ip: 'ip', // 支付者ip，這個(gè)不用理會(huì)也沒(méi)有問(wèn)題
        },
    };
      const result = await pay.transactions_jsapi(params);
      console.log(result);   
}

{
 "id": "091541fc-6sca-55v8-ab24-653a9v313500",
 "create_time": "2022-08-07T16:39:06+08:00",
 "resource_type": "encrypt-resource",
 "event_type": "TRANSACTION.SUCCESS",
 "summary": "支付成功",
 "resource": {
  "original_type": "transaction",
  "algorithm": "AEAD_AES_256_GCM",
  "ciphertext": "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",
  "associated_data": "transaction",
  "nonce": "iOO0tvICpQFb"
 }
}

# key 用商戶平臺(tái)上設(shè)置的APIv3密鑰【微信商戶平臺(tái)—>賬戶設(shè)置—>API安全—>設(shè)置APIv3密鑰】，記為key；
const result = pay.decipher_gcm(ciphertext, associated_data, nonce, key);

{
 "mchid": "3526524578",
 "appid": "wxc2n10fbb6065d4f0",
 "out_trade_no": "2022080711111111",
 "transaction_id": "8520001545602207282059123413",
 "trade_type": "JSAPI",
 "trade_state": "SUCCESS",
 "trade_state_desc": "支付成功",
 "bank_type": "OTHERS",
 "attach": "",
 "success_time": "2022-08-07T16:55:20+08:00",
 "payer": {
  "openid": "drEc8QfY"
 },
 "amount": {
  "total": 1,
  "payer_total": 1,
  "currency": "CNY",
  "payer_currency": "CNY"
 }
}

/* 
 * Created by Asnull.
 * Website:https://lipux.cn/
 */

const WxPay = require('wechatpay-node-v3');
const fs = require('fs');
const request = require('superagent');
const express = require('express');

// 創(chuàng)建服務(wù)器實(shí)例
const app = express();
// 配置解析表單數(shù)據(jù)的中間件
app.use(express.urlencoded({ extended: false }))
app.use(express.json())
// 監(jiān)聽(tīng)端口
app.listen(3031, () => {
    console.log('服務(wù)器啟動(dòng)成功！')
})

// 創(chuàng)建支付實(shí)例
const pay = new WxPay({
    appid: '你的微信小程序appid',
    mchid: '商戶號(hào)',
    publicKey: fs.readFileSync('./apiclient_cert.pem'), // 公鑰
    privateKey: fs.readFileSync('./apiclient_key.pem'), // 秘鑰
});

// 定義一個(gè)獲取支付參數(shù)路由（get請(qǐng)求）
app.get('/pay', payInfo);

// 拿到支付所需參數(shù)
async function payInfo(req, res) {
    // 接收前端傳過(guò)來(lái)的openid
    let openid = req.params.openid;
    const params = {
        description: 'Asnull的支付測(cè)試', // 訂單描述
        out_trade_no: randomNumber(), // 訂單號(hào)，一般每次發(fā)起支付都要不一樣，可使用隨機(jī)數(shù)生成
        notify_url: 'https://pay.lipux.cn/notify_url',
        amount: {
            total: 1, // 支付金額，單位為分
        },
        payer: {
            openid: openid, // 微信小程序用戶的openid，一般需要前端發(fā)送過(guò)來(lái)
        },
        scene_info: {
            payer_client_ip: 'ip', // 支付者ip，這個(gè)不用理會(huì)也沒(méi)有問(wèn)題
        },
    };
    const result = await pay.transactions_jsapi(params);
    console.log(result);
    // 將結(jié)果響應(yīng)給微信小程序前端
    res.send(result);
}

// 回調(diào)路由
app.post('/notify_url', async(req, res) => {
    // 申請(qǐng)的APIv3
    let key = '45c18fdfdgd45f5bc5321201dfdf453f';
    let { ciphertext, associated_data, nonce } = req.body.resource;
    // 解密回調(diào)信息
    const result = pay.decipher_gcm(ciphertext, associated_data, nonce, key);
    // 拿到訂單號(hào)
    let { out_trade_no } = result;
    if (result.trade_state == 'SUCCESS') {
        // 支付成功之后需要進(jìn)行的業(yè)務(wù)邏輯
    }
})

// 訂單號(hào)生成函數(shù)
function randomNumber() {
    const now = new Date()
    let month = now.getMonth() + 1
    let day = now.getDate()
    let hour = now.getHours()
    let minutes = now.getMinutes()
    let seconds = now.getSeconds()
    month = month < 10 ? "0" + month : month;
    day = day < 10 ? "0" + day : day;
    hour = hour < 10 ? "0" + hour : hour;
    minutes = minutes < 10 ? "0" + minutes : minutes;
    seconds = seconds < 10 ? "0" + seconds : seconds;
    let orderCode = now.getFullYear().toString() + month.toString() + day + hour + minutes + seconds + (Math.round(Math.random() * 1000000)).toString();
    return orderCode;
}