Node.js Hello World Example

In previous node.js chapters, we learned what is node.js? and how to setup node.js development environment. Now, we will learn how to create simple node.js hello world application in different ways using node.js command line interface.

 

In node.js, we can create either console or web applications based on our requirements. Here, we will learn both ways to create node.js simple hello world application with examples.

Node.js Hello World Console Application

By using node.js command line interface, we can create a console applications. To open a node.js command-line interface, search for node.js in windows and click on Node.js desktop app like as shown below.

 

Open Node.js command line interface to create console application

 

Generally, when we install a node.js in our machine, we will get a Node.js command-line interface and other required components.

 

After opening Node.js command line interface, type console.log(“Hello World”) command in console and click on enter button that will show the output like as shown below.

 

Node.js Hello World Console Application Example Result

 

If you observe above result, we tried to print a message in node.js shell by typing a message “Hello World”. After we type a message and click on Enter, it returned the string whatever we mentioned in terminal.

Node.js Hello World Web Application

Following are the three main components which required in node.js to create a web application.

 

ComponentDescription
Import Modules By using require directive we can import required modules in application.
Create Server We need to create a server to listen a client requests similar to Apache or IIS server.
Request & Response By using these we can read the client requests and we can return our application response.

Now create a new folder wherever you want in your system, and in that create a file called Helloworld.js and write the code like as shown below.

Helloworld.js

// Importing http core package/module provided by nodejs

var http = require('http');

// Creating a server

http.createServer(function (req, res) {

// Write response as Html(text)

res.writeHead(200, {'Content-Type': 'text/html'});

// Writing static text

res.end('Hello World');

// Server listening on port number 4200

}).listen(4200);

If you observe above code, we are importing http module by using require directive and created the server to listen a request and response on port number 4200.

 

Here, the above code will tells the computer to write “Hello World” if anyone tries to access your computer on port 4200.

 

As of now, you don’t need to worry about the above code, we will learn more about it in next chapters.

Run or Execute JavaScript File in Node.js

The node.js files can be executed by using command line interface program of our computer so open a command prompt (cmd) and navigate to the folder that contains a Helloworld.js file like as shown below.

 

Node.js navigate to execute helloworld.js file

 

Generally, the node.js files can be initiated by entering a command like node <Your_File_Name> so enter a command node Helloworld.js and hit enter button like as shown below.

 

Node.js Hello World Application Enter Command and Execute File

 

Now your computer will work as server so if anyone tries to access your computer with port 4200, then in return they will get a “Hello world” message. To test this, open a browser in your machine and type a url called http://localhost:4200 and click enter, that will show the result like as shown below.

 

Node.js Hello World Application Example Result

 

This is how we can create a console or web applications in node.js based on our requirements. In next chapters, we will learn more about other topics in node.js with examples.