JS SDK代码：

  
  const app = cloudbase.init({
        env: constants.cloudBaseEnv
      });
  const res = await app
    .callFunction({
      name: 'refund',
      data: {
          paymentId: ‘d81cd5415f8c3484016bf06b375cd0e9’,
      }
    })

云函数中代码：

res = await cloud.cloudPay.refund({ 
    nonce_str: 'd782d4875f8c35670157d58d618bc0ed',
    
      out_refund_no:
    
       'd782d4875f8c35670157d58d618bc0edd782d4875f8c35670157d58d618bc0ed',
    
      transaction_id: '4200000751202010189645550551',
    
      total_fee: 100,
    
      refund_fee: 100,
  
  refund_desc: undefined,

  sub_mch_id: '1231409702',

  openid: 'oxZuM5dF30n-yT4bIgP-3BSr8_mY',

  out_trade_no: 'd81cd5415f8c3484016bf06b375cd0e9' 
})

返回错误：

error { errCode: -501007,

errMsg: 'refund:fail Invalid request param' }