在nuxt universal中使用mongoose与serverMiddleware和express。

Question

你好，我目前正在做一个nuxt通用程序，我想用express和mongoose作为后端，从根目录下的api文件夹获取和发布数据到数据库。所以express应该作为一个api端点从nuxt利用的工作。服务器中间件 由nuxt提供。

我在api文件夹下的index.js文件是这样的。

const express = require('express');
const connectDB = require('./db');
const Message = require('./models/Message');
const Visitor = require('./models/Visitor');

// Create express router
const router = express.Router()

// Transform req & res to have the same API as express
const app = express()

router.use((req, res, next) => {
  Object.setPrototypeOf(req, app.request)
  Object.setPrototypeOf(res, app.response)
  req.res = res
  res.req = req
  next()
})

// Get visitor count from db
router.get('/visitors', async (req, res) => {
  const visitors = await Visitor.find({}).countDocuments();
  res.json({ visitors });
});

// Send message to db
router.post('/message', async (req, res) => {
  try {
    // Get message body
    const { name, email, telephone, message } = req.body;

    //Create message & send to db
    const sending = await Message.create({
       name,
       email,
       telephone,
       message,
    });

   res.status(201).json({
     success: true,
     data: sending
   });

 } catch (err) {
   console.log(err);
  }
 });  
});

 // Export the server middleware
export default {
  path: '/api',
  handler: router
}

一切都很正常，直到我从model文件夹中调用mongoose模型（结构是确定的），它给出了这个错误信息。

ERROR  ServerMiddleware Error: Cannot overwrite Message model once compiled.
                 11:59:06

at new OverwriteModelError (node_modules\mongoose\lib\error\overwriteModel.js:20:11)
at Mongoose.model (node_modules\mongoose\lib\index.js:522:13)
at Object.<anonymous> (api\models\Message.js:38:27)

i [HMR] /api (C:\Users\Desktop\js-workspace\js-nuxt-page\api\index.js)
                 11:59:06

谢谢你的任何提示...