Node JS Express Server

Installation

npm install express --save

Hello World

Here is a simple Hello World server that listens on port 3000. To start a server create an instance of express(), like in line 2. Add the listeners, app.get for get requests and app.post for post requests. If you followed the Node JS HTTP Webserver tutorial, express works very simular however all you need to send data is res.send. To start the server call app.listen(port) just like using the HTTP module.

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

app.get('/', function (req, res) {
  res.send('Hello World');
});

app.listen(3000);

Routing

Express makes routing easy with the .get/.post functions, the first argument, in this case '/hello' is the path. In this example, if you were to go to http://localhost:3000/hello you would see You're on /hello!.

app.get('/hello', function (req, res) {
  res.send('You're on /hello!');
});

If you want to add wildcard paths you can add a wildcard marker * at any point in your path. This will route to anything with /hello/ in front of it. To see what URL you are serving use req.url.

app.get('/hello/*', function (req, res) {
  res.send('You're on " + req.url);
});

This is a very basic tutorial on how to use express to process POST body data, serve static files, or serve content with CORS enabled check out our tutorial on Express Plugins.