JavaScript Breakpoints

JavaScript breakpoints are important tools for the debugging process. The reason why breakpoints are used in the JavaScript is many of the times while writing the code for our program, we may encounter few syntax errors and other logic related errors. In this case, the output that we want may not be provided by the code.

So, to find the places where our code is getting problem and solve them to get the output, we debug the whole code and we check and verify the flow of the execution by stopping in each step of the execution process.

Breakpoints are used for the debugging process in many other programming languages by using of the several breakpoint keywords. And specifically, breakpoints stop the execution process and checks each and every step for the errors.

How to Set Breakpoints

To set the breakpoints in the debugger, we can simply set the breakpoints left side of the debugger window for the JavaScript code. The breakpoints can be referenced as red dots or blue depending on the type of tool. So, particularly at every breakpoint, the debugger machine will stop the execution process at runtime and make sure to verify the values. The reason why breakpoints are used at the runtime process is the problem and reason why the code is not running is known at the runtime only. Mostly the errors in the code are not shown and logs are also shown in runtime only.

Breakpoint Examples

1. Visual Studio Code (VS Code):

Visual Studio Code is the most used web browser by many of the developers and almost breakpoints are used handy as it is easy to navigate and examine the errors in the code. The breakpoints can be used straightforward and JavaScript can utilize them.

To open the breakpoints for the JavaScript files in VS code, start by opening the file where you have written the JavaScript code. Now, to locate the breakpoints, just click or select the margin respective to the code line number where you want to keep the breakpoint. It will be represented by a dot of red color. Now, you can easily debug the code by just pressing the F5 button or just clicking the run in the menu and clicking Start Debugging.

Example:

Code:

Output:

2. Browser Developer Tools Breakpoints

We utilise browser tools in recent times for most of the developing processes. Popular browsers that include Chrome, Microsoft Edge, Mozilla Firefox and others have the ability to showcase the developer tools. These developer tools will make sure to set the breakpoints in a direct straightforward manner.

To utilise breakpoints in the browser tools, we can navigate by right clicking or simply pressing F12 which will open several options, then we can choose inspect. Upon clicking, it will open new tab and go to Sources. From here, go to your respective JavaScript file. Now we can set the breakpoints by selecting the line number of the code.

Example:

Code:

Output:

3. Breakpoints using debugger statement

Breakpoints for JavaScript files can be used with the help of the built-in statements. This can be achieved with the help of the debugger statement present in JavaScript. When the engine sees the debugger in the code, then it will stop and the debugger will open and be available.

Example:

Code:

Output:

In the above code for calculating the sum of the two numbers, when the executor sees the debugger statement, it immediately stops the execution and checks if the debugger is open.

These are the few ways how breakpoints can be used in the JavaScript. And there also several other ways breakpoints are used like usage of conditional breakpoints in the browser development tools and makeshift, etc.