在ndoejs和mongoose中保存到数据库后返回数据时调用套接字

问题描述

在将通知保存到数据库后，我想向用户发送通知。

第一个：：我想在databse中保存数据：

秒：我想返回用户FirstName adn lastName

   async CreateNotification(item): Promise<any> {
    const requestModel = new NotificationModel();
    requestModel.sender = item.sender;
    requestModel.reciver = item.reciver;
    requestModel.notificationType = item.notificationType;
    requestModel.sendDate = new Date();
  return  requestModel.save()
        .then((data) => {
            this.GetNOtificationById(data)
            .then(data=>{
              return data;
            })
        });
}

async GetNOtificationById(data) {
    let item = await NotificationModel
        .findOne({ sender: data.sender,reciver: data.reciver,notificationType: data.notificationType })
        .populate({ path: 'sender',select: "firstName lastName" }).exec();
    return item;
}

三：我想返回该数据并在套接字中使用它：

    socket.on('send Notificaiton',(data) => {
    let item;
    notificationRepository.CreateNotification(data)
        .then(data => {
            item = data;
        })
    io.sockets.in(data.reciver).emit('notification',{ id: item.id,senderId: item.sender._id,notificationType: item.notificationType,senderName: item.sender.firstName + ' ' + item.sender.lastName });
})

但是我对此代码有疑问，有时它可以正常工作，有时它在步骤 3 中返回item = {null。

现在我该如何解决这个问题？

解决方法

问题是，您没有等待notification creation。

// Notication
async CreateNotification(item): Promise<any> {
    try {
      const requestModel = new NotificationModel();
      requestModel.sender = item.sender;
      requestModel.reciver = item.reciver;
      requestModel.notificationType = item.notificationType;
      requestModel.sendDate = new Date();
      const data = await requestModel.save()
      const result = await this.GetNOtificationById(data)
      return result 
    } catch(err) {
      console.log(err)
      throw err
    }
}

socket.on('send Notificaiton',async (data) => {
  try {
    const item = await notificationRepository.CreateNotification(data)
    if (item) {
      io.sockets.in(data.reciver).emit('notification',{ id: item.id,senderId: 
      item.sender._id,notificationType: item.notificationType,senderName: 
      item.sender.firstName + ' ' + item.sender.lastName });
    } else {
      console.log('Item does not exist',item)
    }
  } catch (err) {
    console.log('Error while creating item: ',err)
  }