Smart auto-importing of Mongoose models in a Node.js API.

Overview

Hello! In this article, we will learn how to avoid long import statements for your Mongoose models. All the snippets in this blog can be found in this repo.

Checkout into the main branch to see how one would normally import the models using the require keyword. Looking at the repo, you will notice that it gets tedious to keep track of the definitions of the models within your application. What's more, you need to know how the models are being exported. That is, they can be exported with a name different from the one used in the script definition, which is a common pattern. Or they could be exported as default exports meaning attempting to require them as named modules would definitely raise an error.

Explanation & Demo

In the with-smart-import branch, you will find that all models are registered in the lib/createApp.js file. lib/createApp function deals with creating an instance of the Express app, registering all the routes, the middleware, and finally creating a MongoDB connection. As such, it's the best place to register all our models and make them accessible to any route through the Express Request object.

// lib/createApp.js
// import your models
const models = require('../models);

async function createApp() {
const app = express();
 // other code here

 // register models
app.use(async (req, res, next) => {
  req.models = models;

// call the next middleware
 await next()
});
}

Then in your route, you can simple do:

// routes/users.js
const express = require('express');

const router = express.Router();

router.get('/users', async (req, res) => {
 try {
 // grab the User model from the req. object
  const { models: { User } } = req;
 const users = await User.find().exec();
 console.log(users);
} catch(error) {
 console.error(`Error here: ${error.message}`)
}
});

And voila!

Bonus

As an experienced Node.js/JavaScript developer, I've adopted ways of making my code shorter and readable. Normally, you'll find routes being registered individually in the server.js file. For instance, app.use('/users', userRoutes), then app.use('/clubs', clubRoutes) and so on and so forth. This to me is a little repetitive. I prefer to classify them as public and protected and register them in one line:

// routes/public/index.js
// import all your unprotected routes here, then export them as an array!
module.exports = [
 routeOne,
 routeTwo,
];

then in your server file, or in lib/createApp.js you iterate over them and call app.use(): publicRoutes.forEach((route) => app.use(route)). See this pattern in use here and here!

Thanks for reading!