Hello World

Hello World

Writing a Node.js program is as simple as creating a new file with a .js extension. For example you could create a simple hello_world.js file with the following content:

console.log('Hello World!');

After you have saved the file, you can execute it from your terminal like so:

node hello_world.js

and the ouput will be

Hello World

Hello World on a server

Now printing hello world to a terminal isn’t all that exciting. Let’s take the next step and write a program that responds to hello world via http. We’ll call the file hello_server.js and put the following code into it:

var http = require('http');

var server = http.createServer(function(req, res) {
  res.writeHead(200);
  res.end('Hello World, I am in the server!');
});

server.listen(8080);

Now let’s run this program from the terminal by typing:

node hello_server.js

Testing the server is as simple as opening a new browser tab, and navigating to the following url: http://localhost:8080/. As expected, you should see a response that reads:

‘Hello World, I am in the server!’.