Mongoose model.save() stuck pending? - node.js

Question

I am using mongoose to handle my schemas, with MongoDB, but when trying to save a new entry to a collection the save() method appears to be stuck, neither the then() method or the catch() method of the promise appear to be called.
Does anyone have any ideas?
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
// const Promise = require('bluebird');
const config = require('./config');
const UserSchema = new Schema({
email: { type: String, required: true, index: { unique: true } },
name: { type: String, required: false },
password: { type: String, required: true }
});
const User = mongoose.model('User', UserSchema);
console.log('config.database.url', config.database.url);
mongoose.Promise = global.Promise;
return mongoose.createConnection(config.database.url, {
useMongoClient: true
})
.then((connection) => {
const user = new User({
email: 'someuser#somedomain.com',
password: 'xxxxx'
});
const prom = user.save();
// Displays: 'promise: Promise { <pending> }'
console.log('promise:', prom);
return prom
.then((result) => {
// Don't see this output
console.log('result:', result);
})
.catch((error) => {
// Don't see this output either
console.log('error:', error);
});
})
.catch((error) => {
console.log(error);
});
Environment: nodejs 8.9.0, node modules: Mongoose 4.13.6, mongodb 2.2.33

Answer 1

A little more experimenting and it would appear that I need to ensure the model is tied to the connection, such that:
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
// const Promise = require('bluebird');
const config = require('./config');
const UserSchema = new Schema({
email: { type: String, required: true, index: { unique: true } },
name: { type: String, required: false },
password: { type: String, required: true }
});
let User;
console.log('config.database.url', config.database.url);
mongoose.Promise = global.Promise;
return mongoose.createConnection(config.database.url, {
useMongoClient: true
})
.then((connection) => {
// associate model with connection
User = connection.model('User', UserSchema);
const user = new User({
email: 'someuser#somedomain.com',
password: 'xxxxx'
});
const prom = user.save();
// Displays: 'promise: Promise { <pending> }'
console.log('promise:', prom);
return prom
.then((result) => {
// Don't see this output
console.log('result:', result);
})
.catch((error) => {
// Don't see this output either
console.log('error:', error);
});
})
.catch((error) => {
console.log(error);
});
Alternatively we should use the connect() method that will work with the model associated via mongoose.model.
For createConnection() can be used to create multiple connections, so using a 'global' model is not supported, from what I can tell.
Saying all this it would be nice if save() didn't simply block.
Note: In researching a refinement to my answer I came across the following: Queries hang when using mongoose.createConnection() vs mongoose.connect()