Mongoose Schema hasn't been registered for model

Question

I\'m learning the mean stack and when I try to start the server using

npm start

I get an exception saying that:

schema has         


        

Answer 1

It's not an issue with model export. I had the same issue.

The real issue is that require statements for the models

var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/news');
require('./models/Posts');
require('./models/Comments');

were below the routes dependencies. Simply move the mongoDB dependencies above the routes dependencies. This is what it should look like:

// MongoDB
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/news');
require('./models/Posts');
require('./models/Comments');

var routes = require('./routes/index');
var users = require('./routes/users');

var app = express();

Answer 2

My problem was sort out using the below

adminModel.findById(req.params.id).populate({ path: "users", model: userModel //User collection name })

Answer 3

I also facing same issue but i resolved by removing module.exports

module.exports = mongoose.model('user', userSchema); // remove module.exports
and use like:: mongoose.model('user', userSchema);

const mongoose = require('mongoose');
const ObjectId = require('mongoose').ObjectId;

var userSchema = new mongoose.Schema({
    Password: { type: String },  
    Email: { type: String, required: 'This field is required.', unique:true },  
    songs: [{ type: ObjectId, ref: 'Songs'}]
});

// Custom validation for email
userSchema.path('Email').validate((val) => {
    emailRegex = /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
    return emailRegex.test(val);
}, 'Invalid e-mail.');

// module.exports = mongoose.model('user', userSchema);  // remove 'module.exports ='
mongoose.model('user', userSchema); // resolved issue

Answer 4

I used the following approach to solve the issue

const mongoose = require('mongoose');
const Comment = require('./comment');

const PostSchema = new mongoose.Schema({
            title: String,
            link: String, 
            upvotes: { type: Number, default: 0 },
            comments: [{ type: mongoose.Schema.Types.ObjectId, ref: Comment }]
        });
mongoose.model('Post', PostSchema);

Please look, here ref don't have string type value, now it's referring to Comment schema.

Answer 5

In my case, this issue because I haven't included the model or ref model into the application. So you should required Post model and Comment model in your node application.

Answer 6

I was also facing the same problem. The solution to my problem was looking at the ref parameter which had a different name compared to the model I was actually exporting and hence no such model was found.

userSchema.virtual('tasks', {
    ref: 'Task',
    localField: '_id',
    foreignField: 'owner'
})
  

Whereas what I had actually exported was :-

const Tasks = mongoose.model('Tasks', taskSchema)

module.exports = Tasks

After rectifying the Task as Tasks my problem was solved