Mongoose not resolving callback queries? - node.js

Question

I have been working on this project for 2 years now, and I'm thinking this was caused by the recent update, but am wondering if there are any kind, intelligent, Mongoose/NoSQL DBA, souls out there who would do the awesome service of helping me either track-down, and/or resolve this issue.
So, as you can see below, this is a simple mongoose find query over express to MongoDB. This is rather evident, at a high-level, and for most devs, the interactions will be natural, as any Mongo, Express, Node Stack using Mongoose.
The is issue is that, when I send this query, disregarding environment (a production project), it does not resolve.
The "data" seems to get lost somewhere, and therefore, the query simply never resolves.
It's a simple setup, really a test endpoint, so help out, run it through, and send some feedback.
Greatly Appreciated!
Model.js
const mongoose = require('mongoose');
const mongoosePaginate = require('mongoose-paginate');
const Schema = mongoose.Schema;
const TestSchema = new Schema({
data: {
type: String,
unique: false,
required: true
},
}, {
timestamps: true
});
TestSchema.plugin(mongoosePaginate);
module.exports = mongoose.model('Test', TestSchema);
Constructor.js
class Constructor {
constructor() {}
getAll() {
return TestSchema.find({}, function (err, tests) {})
}
}
module.exports = Constructor
db.js
let mongoose = require('mongoose')
// Connect to db
mongoose.connect('mongodb://localhost:27017/test', {useNewUrlParser: true, useUnifiedTopology: true }, err => {
if (err)
return console.log("Cannot connect to DB")
connectionCallback()
console.log("DB Connected")
});
let connectionCallback = () => {}
module.exports.onConnect = cb => {
connectionCallback = cb
}
App.js
const express = require('express');
const app = express();
const ip = require('ip');
let db = require('./db')
const router = express.Router();
const port = 8888;
const http = require('http').createServer(app);
let ipAddress = 'localhost'; // only works to the local host
try {
// will enable the server to be accessed from the network
ipAddress = ip.address();
} catch( err ){
console.err( err );
}
http.listen(port, ipAddress,
() => {
let message = [
`Server is running at ${ipAddress}:${port}`,
];
console.log( ...message )
});
db.onConnect(() => {
let Constructor = require("./pathTo/Constructor")
let construct = new Constructor()
app.use('/api', router.get('/test', function(req, res) {construct.getAll()}))
})

Answer 1

Your problem is with the constructor.js getAll function, as you are returning also and passed a callback also, the promise will never be resolved. You should either resolve the promise or return the response from the callback.
Resolve Promise:
class Constructor {
constructor() {}
async getAll() {
return await TestSchema.find({})
}
}
module.exports = Constructor
Return from callback:
class Constructor {
constructor() {}
getAll() {
TestSchema.find({}, function (err, tests){
return tests.
})
}
}
module.exports = Constructor

Answer 2

I ended up just scaling the project for production. I put the connectionCallback in a class and called it with the createConnection mongoose function.
Looks like this:
mongoose.Promise = global.Promise;
const url = 'mongodb://localhost/db'
const connection = mongoose.createConnection(url, options);
//load models
require('/models').connectionCallback();
modules.export = connectionInstance;
Please note, I am no longer using express!