Build an Application in NodeJS Express and MongoDB - Part 1

Introduction

If you’re building applications using NodeJS and the Express framework, you may want to interact with a MongoDB database from your code. Fortunately, this task is easy to accomplish using the Mongoose package for Javascript. In this first article of our two-part series, we’ll show you how to create an application using NodeJS, Express and MongoDB. We’ll start by walking you through the process of installing the needed items and doing the necessary setup; after that, we’ll look at the code.

Prerequisites

Before we get started, let’s go over the prerequisites that need to be in place for this project:

• Make sure that you have MongoDB installed and working on your machine. On Linux systems, you can use the command mongod --version to get the version number of your MongoDB installation.

• You’ll need to have some basic knowledge of Javascript, especially the NodeJS framework. You should also know how to use NPM, the package manager for NodeJS, to install the mongoose package. Mongoose is a tool for MongoDB that manages data relationships and validates schemas. It can be thought of as a layer that sits on top of the MongoDB driver for NodeJS.

Install NodeJS and NPM

We’ll need to install NodeJS before we can create our application with MongoDB. If you’re on a Windows or Mac operating system, you can click the download link for the Node installer.

Installing NodeJS in your linux system

If you’re running an Ubuntu or Debian distribution of Linux that uses the APT-GET repository, you can use the command shown below to install NodeJS:

If you’re running a Red Hat distribution of Linux that uses the YUM repository, such as Fedora or CentOS, use this command to install NodeJS:

Once you’ve completed the installation, you can verify the version number by typing node -v in the terminal; similarly, you can use npm -v to get the Node Package Manager version.

Create a database in MongoDB

Next, we’ll initialize and start the MongoDB interactive interface so that we can create a database:

You’ll be prompted for a password. After entering it, use the command mongo to start an instance of the Mongo shell.

To create a database in MongoDB, just type the command use followed by a database name. It’s ok if this database name doesn’t yet exist– MongoDB will create it automatically and switch into it. You can see how it works below:

Start the project by creating a directory for the Node app

The first step in getting our project started is to set up the folder which will contain our Node application. We’ll create a directory in the terminal using the bash commands shown below, and then we’ll navigate into the directory:

Next, we’ll create a package.json file. This file usually holds and manages the Node packages installed locally. It also includes the metadata of the project in the folder.

To create a new NodeJS application, we’ll run the command below:

NOTE: The -y flag stands for yes in response to the question asking if you still want to proceed with the command.

Install the NPM dependencies for the Node app

We’ll use the following command to install all the dependencies needed to set up our Node application:

• Notice that we added the @ sign before the number. This ensures that we get the latest version of the current npm package that we are installing.

Open your code editor

Before proceeding with the next steps, make sure you have a code editor that suits your needs. Some good choices include Sublime, VSCode and Atom.

We’ll start by creating a model folder which will contain our db.js file:

Inside this db.js file, we’ll create our database connection using the Mongoose package in NodeJS. Here’s how it’s done:

• First, create a constant variable that will require the Mongoose package:

• Then, set the connection and create a callback function that will return the output:

• Keep in mind that the default port used for MongoDB is 27017.

In the next section, we create the schema for the Node application:

student.model.js

Finally, we start the Express server by creating our root file app.js:

To run your code, use the command node app.js in your terminal. In your browser’s address bar, be sure to use the localhost port 5050.

You’ll notice that there is an error getting the server– this occurs because we haven’t yet set up the route for the controller of the node application. We’ll tackle that task in the next article of the series.

Conclusion

When you’re building an application using NodeJS, Express and MongoDB, it’s important to make sure everything you need is installed and configured correctly. In this article, we covered those key steps in the process, and we also walked through the code needed to make the application work. The next article will pick up where we left off, detailing the remaining tasks needed to complete our NodeJS application.

Just the code

In this article, we reviewed quite a bit of code. Shown below is the sample code in its entirety:

db.js

student.model.js

app.js