Basic Node.js Express application

So far we have done a few daily tips like Read and write a JSON file, Posting to Twitter via Node.js, Posting to Facebook via Node.js and RSS Reader in Node.js with node.js. But we never really got around to creating a basic browser-based application.

So let’s spend today creating a Hello World in Node.js in combination with express

Installing node.js permalink

To install node.js we simply have to go to their website and download the package. Then go ahead and follow the install instructions afterward.

Node.js download

Creating our first node.js app permalink

To create a node.js app, we use our terminal.

If you are on Mac I’d suggest using iTerm2. The best terminal for Mac!

Run the following code in your terminal.

mkdir firstapp
cd firstapp

These commands will mkdir make directory called firstapp and cd change directory into this newly created directory.

Node comes with a CLI (Command Line Interface) so we can use the following command to turn this directory into a node.js app.

npm init

This will create a package.json file in our folder. This command will prompt some questions in our terminal. You can enter through these.

Installing Express in our node.js app permalink

Express is a web framework for node.js. It comes with useful tools that are easy to use and understand. Because of this, it’s a widely adopted standard in node.js web development. Especially when you are a beginner I would suggest using Express.

Make sure you are still in the firstapp directory and run the following command.

npm install express --save

This command will install the package Express, and the --save option will save this in our package.json

We should now see a node_modules folder in our project automatically.

Creating our node.js index.js file permalink

Of course we need a file to work from, open your editor of choice and add our newly created project.

Create a file in the root called index.js and add the following code to it:

const express = require('express');
const app = express();
app.get('/', function (req, res) {
  res.send('Node.js is amazing! ⚡️');
});
app.listen(3000, function () {
  console.log('Example app listening on port 3000!');
});

Explained;

const express = require('express');
const app = express();

The first line says we need to require the express package, and them we start a new app which is based on `Express.

app.get('/', function (req, res) {
  res.send('Node.js is amazing! ⚡️');
});

This says if someone browser to the / endpoint we send the result (res) of Node.js is amazing! ⚡️.

app.listen(3000, function () {
  console.log('Example app listening on port 3000!');
});

This tells our app to listen on port 3000 and when it does return to the console it’s up and running.

Running our Node.js Express app permalink

To run our newly created application we run the following command in our terminal (still in the firstapp directory)

node index.js

The terminal now should show the following:

Example app listening on port 3000!

When we go to http://localhost:3000/ in our browser we should see ‌Node.js is amazing! ⚡️

Amazing, we created our very first browser Node.js application!

You can download this project on GitHub.

Thank you for reading, and let’s connect! permalink

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