MEAN：类型错误：......是不是构造

Question

我很新的发展和工作我的方式，通过这意味着教程： MEAN Stack Front To Back [Part 3] - User Model & Register

我读过这里有几个问题，但无法找到相关答案。

这里是主错误代码：

Server started on port 3000 
Database Error MongoError: failed to connect to server [localhost:27017] 
on first connect 
TypeError: User is not a constructor 
at router.post (/Users/user/Desktop/Development/meanauthapp/routes/users.js:12:16) 

这是奇怪的，因为我的mongod终端状态的：

2017-03-15T09:52:49.306-0700 I NETWORK 
[thread1] waiting for connections on port 27017 
2017-03-15T09:52:54.514-0700 I NETWORK 
[thread1] connection accepted from 127.0.0.1:49188 #1 (1 connection now open) 
2017-03-15T09:52:54.515-0700 I NETWORK 
[conn1] received client metadata from 127.0.0.1:49188 conn1: 
{ application: { name: "MongoDB Shell" }, 
driver: { name: "MongoDB Internal Client", version: "3.4.1" }, 
os: { type: "Darwin", name: "Mac OS X", architecture: "x86_64", version: "15.6.0" } } 

/routes/users.js

/*---------------Dependencies-------------*/ 
const express  = require('express'); 
const router   = express.Router(); 
const User    = require('../config/database'); 
const passport  = require('passport') 
const jwt     = require('jsonwebtoken'); 
/*----------------------------------------*/ 


/*---------------Register-----------------*/ 
router.post('/register', (req, res, next) => { 
    let newUser = new User({ 
     name:  req.body.name, 
     email:  req.body.email, 
     username: req.body.username, 
     password: req.body.password 
    }); 

    User.addUser(newUser, (err, user) => { 
     if(err) { 
      res.json({success: false, msg:'Failed to register user'}); 
     } else { 
      res.json({success: true, msg: 'User Registered'}) 
     } 
    }); 
}); 
/*----------------------------------------*/ 


/*---------------Authenticate---------------*/ 
router.post('/authenticate', (req, res, next) => { 
    res.send('AUTHENTICATE') 
}); 
/*----------------------------------------*/ 


/*-----------------Profile------------------*/ 
router.get('/profile', (req, res, next) => { 
    res.send('PROFILE') 
}); 
/*----------------------------------------*/ 


module.exports = router; 

出现错误的行是：let newUser = new User（{

/config/database.js

module.exports = {  database: "mongodb://localhost:27017/famjam", 
secret  : "yoursecret" } 

/models/users.js

const mongoose = require('mongoose'); 
const bcrypt  = require('bcryptjs'); 
const config  = require('../models/database'); 


/*User Scheme*/ 

const UserScheme = mongoose.Scheme({ 
    name: { 
     type: String 
    }, 
    email: { 
     type: String, 
     required: true 
    }, 
    username: { 
     type: String, 
     required: true 
    }, 
    password: { 
     type: String, 
     required: true 
    } 
}); 

const User = module.exports = mongoose.model('User', UserScheme); 

module.exports.getUserById = function(id, callback) { 
    User.findById(id, callback); 
} 


module.exports.getUserbyUsername = function(username, callback) { 
    const query = {username: username} 
    User.findOne(query, callback); 
} 


module.exports.addUser = function(newUser, callback) { 
    bcrypt.genSalt(10, (err, salt) => { 
     bcrypt.hash(newUser.password, salt, (err, hash) => { 
      if(err) throw err; 
      newUser.password = hash; 
      newUser.save(callback); 
     }) 
    }); 
} 

app.js

/*---------------Dependencies-------------*/ 
const express  = require('express'); 
const path    = require('path'); 
const bodyParser = require('body-parser'); 
const cors    = require('cors'); 
const passport  = require('passport'); 
const mongoose  = require('mongoose'); 
const users    = require('./routes/users') 
const config   = require('./config/database') 
/*----------------------------------------*/ 


/*---------------Database-------------*/ 
mongoose.connect(config.database); 

mongoose.connection.on('connected',() => { 
    console.log('connected to database ' +config.database) 
}); 

mongoose.connection.on('error', (err) => { 
    console.log('Database Error '+err) 
}); 
/*----------------------------------------*/ 


/*------------------App-------------------*/ 
const app = express(); 

// Port Number 
const port = 3000; 

app.listen(port,() => { 
    console.log('Server started on port '+port) 
}); 

//CORS Middleware 
app.use(cors()); 

// Body Parser Middelware 
app.use(bodyParser.json()) 

// Set Static Folder 
app.use(express.static(path.join(__dirname, 'public'))); 

app.use('/users', users) 
/*----------------------------------------*/ 


/*---------------Index Route--------------*/ 
app.get('/', (req, res) => { 
    res.send('Invalid Endpoint') 
}); 


app.get('/myaccount', (req,res) =>{ 
    res.render('myaccount') 
}) 

Answer 1

如果req.body是具有objectname, email, username和password集，你应该能够创建新的用户简单地做：

let newUser = new User(req.body); 

，因为要传递到构造函数有4个不同属性的对象，您收到此错误，同时期待接收请求主体。