1. Create a file named server.js in the root directory of your project.

2. Add the following code to the file.

const http = require('http');

This will handle the server's request and response.

3. Create a server using createServer() method.

http.createServer().listen(4500);

• This method can take a function as a parameter. We use this createServer() method to create a server. The listen() method is used to listen to the port number means the server will start on the port number 4500.

• You can check this on official documentation of http (opens in a new tab).

4. Now, You have to pass two functions req and res as a parameter to the createServer() method.

http.createServer((req, res) => {
 
}).listen(4500);

• This is arrow function and the syntax of the arrow function is abc((req, res) => {}). First bracket is for the parameter and the second bracket is for the function. You can check this on official documentation of arrow function (opens in a new tab).
• The req parameter is used to get the request from the client and the res parameter is used to send the response to the client.

5. I assume that no one actually sends a request to the server. So, we will send a response to the client.

 
http.createServer((req, res) => {
    res.write('Hello World');
    res.end();
}).listen(4500);

• We need to use write() method to send the response to the client. The write() method can take a string or a buffer as a parameter. We can also use end() method to end the response. You can check this on official documentation of http (opens in a new tab).

6. Now, run the server using the following command.

node server.js

7. Now, open the browser and type localhost:4500 in the address bar. You will see the following output.

Hello World

8. You can also send a html tag to the client.

http.createServer((req, res) => {
    res.write('<h1>Hello World</h1>');
    res.end();
}).listen(4500);

• But remember you have to run the server again.

1. FOR EXAMPLE: We will create a function named data() and we will pass the req and res as a parameter to the function.

const data = (req, res) => {
    res.write('Hello World');
    res.end();
}
 

or

function data(req, res) {
    res.write('Hello World');
    res.end();
}

2. Now, we will pass the data function as a parameter to the createServer() method.

http.createServer(data).listen(4500);

3. Now run the server using the following command.

node server.js

• You will get the same output as the previous one.

Basically, arrow function is a short form of the function just use const function_name = (parameter) => {function body} instead of function function_name(parameter) {function body}. You can check this on official documentation of arrow function (opens in a new tab).

1. We just copy the data() function and paste it in the createServer() method.

old

http.createServer(
// function body
).listen(4500);

new

http.createServer(
 
// function body
(req, res) => {
    res.write('Hello World');
    res.end();
}
 
).listen(4500);

📌 Simplified Code

function multiply(a, b) {
    return a * b;
}
console.log(multiply(2, 3));

const multiply = (a, b) => a * b;
console.log(multiply(2, 3));

here return is not required because it is a single line function.

Additionally you can check the js tutorial which is available on my website. You can check this on official documentation of arrow function (opens in a new tab).