Node.js tutorial: Get started with Node

{
  "dependencies": {
	"express": "^5.1.0"
  }
}

This is how dependencies are defined in NPM. It says the application needs the express dependency at version 5.1.0 (or greater).

Setting up the Express server in Node

Express is one of the most-deployed pieces of software on the Internet. It can be a minimalist server framework for Node that handles all the essentials of HTTP, and it’s also expandable using “middleware” plugins.

Since we’ve already installed Express, we can jump right into defining a server. Open the example.js file we used previously and replace the contents with this simple Express server:

import express from 'express';

const app = express();
const port = 3000;

app.get('/', (req, res) => {
  res.send('Hello, InfoWorld!');
});

app.listen(port, () => {
  console.log(`Express server at http://localhost:${port}`);
});

This program does the same thing as our earlier http module version. The most important change is that we’ve added routing. Express makes it easy for us to associate a URL path, like the root path (‘/’), with the handler function.

If we wanted to add another path, it could look like this:

app.get('/about', (req, res) => {
  res.send('This is the About page.');
});

Once we have the basic web server set up with one or more paths, we’ll probably need to create a few API endpoints that respond with JSON. Here’s an example of a route that returns a JSON object:

app.get('/api/user', (req, res) => {
  res.json({
	id: 1,
	name: 'John Doe',
	role: 'Admin'
  });
});

That’s a simple example, but it gives you a taste of working with Express in Node.

Conclusion

In this article you’ve seen how to install Node and NPM and how to set up both simple and more advanced web servers in Node. Although we’ve only touched on the basics, these examples demonstrate many elements that are required for all Node applications, including the ability to import modules.

Whenever you need a package to do something in Node, you will more than likely find it available on NPM. Visit the official site and use the search feature to find what you need. For more information about a package, you can use the npms.io tool. Keep in mind that a project’s health depends on its weekly download metric (visible on NPM for the package itself). You can also check a project’s GitHub page to see how many stars it has and how many times it’s been forked; both are good measures of success and stability. Another important metric is how recently and frequently the project is updated and maintained. That information is also visible on a project’s GitHub Insights page.