Setting Up the Application (Manual)

Please note ⚠️

If you used the @command-shift/create-backend-app script, you do not need to follow these manual steps. The script has already done all the required setup mentioned on this page. Feel free to read through if you want a better understanding of what the script did.

Manually setting up the app

Now that we have a blank repo, it's time to start setting up a basic Express application.

Express

1. Install express as a dependency:

   npm i -S express

2. Make a src directory inside your project folder. Put an app.js file in there.

   1. Require express at the top of the file: const express = require('express');

   2. Call express as a function, and assign it to a const called app: const app = express();

   3. We know that we will need to be able to access the request.body in this project, so we should also configure the app to use express.json: app.use(express.json());

   4. Finally, export your app at the bottom of the file with module.exports = app;

3. Make a file in the root of project called index.js.

   1. Require your app at the top of this file.

   2. Declare a const called APP_PORT and set it to a value of 4000. This is the port that we will configure our app to listen on.

   3. Call app.listen as a function. The first argument it takes will be APP_PORT.

   4. The second argument app.listen will take is an arrow function. In this arrow function you should console.log(`App is listening on port ${APP_PORT}`)

Your src/app.js should now look like this:

const express = require('express');
 
const app = express();
 
app.use(express.json());
 
module.exports = app;

And your index.js should look like this:

const app = require('./src/app.js');
 
const APP_PORT = 4000;
 
app.listen(APP_PORT, () => {
  console.log(`App is listening on port ${APP_PORT}`)
})

If you run the command node index.js in the terminal, you should see that your app is running. It won't do anything yet though, we haven't given it any routes or controllers.

Right now, we will need to restart our app every time we make any changes to the code. This can get tedious fast. To help make the development cycle a bit smoother, we will use nodemon.

Nodemon

Nodemon (short for node demon), is a package which will watch our project files and wait for them to be updated. When it detects this, it will restart our application. This means that any changes to the code will be reflected in our app right away.

1. Install nodemon as a dev dependency using the -D flag by running npm i -D nodemon

2. Add a start script to your package.json. It should run the command nodemon index.js

3. Test your start script by running npm start in your terminal.

Finally

Add a get route to / in your app.js. It should return a 200 status code and a Hello World string. Run your app and send a GET request to localhost:4000 in postman. If you get a Hello World then you know that your app is working.