JavaScript Debugging

What is Debugging in JavaScript?

In JavaScript, debugging is used to find errors or bugs in the source code of any software. In simple words, debugging is a process in which we examine the JavaScript code find the errors, and fix them.

Developers can make some mistakes while coding it can be logical, syntax, or runtime errors. When an error occurs in a program it is called a bug.

Sometimes a code may contain certain mistakes. Being a scripting language, JavaScript didn't show any error message in a browser. But these mistakes can affect the output.

The best practice to find out the error is to debug the code. The code can be debugged easily by using web browsers like Google Chrome, and Mozilla Firefox.

To identify these errors we need debuggers that can go through the entire code or program, which identify and fix the mistakes.

Use a JavaScript Debugger

In JavaScript, we use the debugger in the code to stop the execution of code forcefully and call the debugging function. This function is executed if any debugging is needed at all else there is no requirement to perform this action.

When a script is loaded into a debugger, it can be run one line at a time or it can be instructed to halt at certain breakpoints. When a program execution is paused, the programmer can assess the script's state and variables to identify any errors. The programmer can also monitor the variables for changes in their values.

In debugging, we generally set breakpoints to examine each line of code step by step. There is no requirement to perform this task manually in JavaScript.

JavaScript provides a debugger keyword to set the breakpoint through the code itself. The debugger stops the execution of the program at the position it is applied. Now, we can start the flow of execution of the program manually. If an exception occurs, the execution will stop again on that particular line.

Example

Let's take a program in JavaScript to see the debugging:

Output:

Using the console.log () method

With the use of the console.log() method, we can print the message in the web browser console. It can print primitive values, objects, variable values, etc.

Using the console.log() method, we can print the variable value in the console we want to debug. We have another way in which the JavaScript values can be displayed in the console of the window.

The console.log() method displays the result in the console of the browser. If there is any mistake in the code, it generates the error message.

For Example:

Output:

How does the debugging process work?

The debugging process typically requires the following steps:

Error identification

Developers, testers, and end-users report bugs when they discover while testing or using the software. The developer locates the exact location of the code or the exact line of code or code module that is causing the bug. It can be a tedious and time-consuming process.

Error analysis

When a coder analyses the error by recording all program state changes and data values. We can prioritize the bug fix based on its impact on software functionality. Our software team helps us fix bugs and achieve development goals and requirements.

Fix and validation

Developers can fix the bugs and run tests to ensure the software continues to work as expected. We may also write a new test check if the bugs recur in the future.

Debugging vs testing

They are complementary processes that help us to ensure that the software programs run as they should. After we write a complete section or part of a code, developers can test the code to identify bugs and errors. Once we find the bugs coders or programmers can begin the process of debugging and they can work towards ridding the software of any errors.

Importance of Debugging in JavaScript

Improve software quality

With the help of debugging, we can identify and fix errors which helps us to improve the software quality and reduce the bugs in future releases.

Saving time and resources

It also helps us to catch the errors and bugs in the earlier stage of the software development cycle and it saves time and resources of the organization.

Enhancing user satisfaction

It also helps us to provide a better user experience as debugging helps in ensuring that the software is functioning as per requirement. This enhances the user experience.