Here we will see how the non blocking programming works and how the control goes from one program to another without sequence.

Example for Non-Blocking:

Let us create a text file file_2.txt. Now write some content in the file_2.txt

Let us write the below content:

Content for non-blocking example:The runtime environment interprets JavaScript using Google's V8 JavaScript engine.

Now create a js file demo.js and write the following code:

var filesys_nb = require("fs"); /*importing the file system module*/

filesys_nb.readFile('file_2.txt', function (error, output) {
    if (err) return console.error(error);
    console.log(output.toString());
});

console.log("This is the end of the no blocking code.");

Now execute the following command

username@machinename:~$ cd path of the file
username@machinename: path of the file$ node demo.js

The above example explains the concept of non-blocking calls, here the program does not wait for reading file_2.txt and it just forwards the control to the code console.log("This is the end of the no blocking code."); and simultaneously continues reading the file_2.txt without blocking. The execution of Non-blocking programs is not sequential,

Output:

Executed first: This is the end of the no blocking code.

Executed second:Content for non-blocking example:The runtime environment interprets JavaScript using Google's V8 JavaScript engine.