统一下单

除付款码支付场景以外，商户系统先调用该接口在微信支付服务后台生成预支付交易单，返回正确的预支付交易会话标识后再按Native、JSAPI、APP等不同场景生成交易串调起支付。 官方JSAPI文档 Native官方文档 官方APP文档 官方H5文档 官方小程序支付文档

const { Formatter, Hash } = require('wechatpay-axios-plugin')

// 直连模式 NATIVE 支付场景
wxpay.v2.pay.unifiedorder.post({
  mch_id,
  appid,
  body,
  out_trade_no,
  notify_url,
  total_fee,
  trade_type: 'NATIVE',
})
.then(
  ({ 
    data: {
      return_code,
      result_code,
      trade_type,
      code_url,
    }
  }) => code_url
)

// 直连模式 JSAPI 支付场景
wxpay.v2.pay.unifiedorder.post({
  mch_id,
  appid,
  body,
  out_trade_no,
  notify_url,
  total_fee,
  trade_type: 'JSAPI',
  sign_type,
})
.then(
  ({
    data: {
      return_code,
      result_code,
      trade_type,
      prepay_id,
    }
  }) => {
  const nonceStr = Formatter.nonce();
  const timeStamp = '' + Formatter.timestamp();
  const packageStr = 'prepay_id=' + prepay_id;
  const signType = previousSignType || 'MD5';
  return { 
    appId,
    timeStamp,
    nonceStr,
    package: packageStr,
    signType,
    paySign: Hash.sign(
      signType,
      { appId, timeStamp, nonceStr, package: packageStr, signType },
      apiv2Secret
    )
  }
})

// 直连模式 APP 支付场景
wxpay.v2.pay.unifiedorder.post({
  mch_id,
  appid,
  body,
  out_trade_no,
  notify_url,
  total_fee,
  trade_type: 'APP',
  sign_type,
})
.then(
  ({
    data: {
      return_code,
      result_code,
      trade_type,
      prepay_id: prepayid,
    }
  }) => {
  const noncestr = Formatter.nonce();
  const timestamp = '' + Formatter.timestamp();
  const packageStr = 'Sign=WXPay';
  const signType = previousSignType || 'MD5';
  return { 
    appid,
    partnerid,
    prepayid,
    package: packageStr,
    timestamp,
    noncestr,
    sign: Hash.sign(
      signType,
      { appid, partnerid, prepayid, package: packageStr, timestamp, noncestr },
      apiv2Secret
    )
  }
})

// 直连模式 MWEB 支付场景
wxpay.v2.pay.unifiedorder.post({
  mch_id,
  appid,
  body,
  scene_info,
  out_trade_no,
  notify_url,
  total_fee,
  trade_type: 'MWEB',
})
.then(
  ({ 
    data: {
      return_code,
      result_code,
      trade_type,
      mweb_url,
    }
  }) => mweb_url
)