Node Debugging

Debugging is an essential part of software development that helps developers identify and fix errors. This ensures that the application runs smoothly without causing errors. NodeJS is a JavaScript runtime environment that provides various debugging tools for troubleshooting the application.

• They help in identifying runtime errors.
• Improves code efficiency by detecting memory leaks.
• Enables developers to monitor application execution flow.
• Ensures error-free and reliable applications.

How You Usually Debug NodeJS Applications

Generally, beginners use console.log() for debugging, which can become messy and inefficient. While it's a quick way to check values, it's not ideal for complex debugging scenarios.

• console.log() can clutter your code and slow down development as you add and remove log statements. It's also hard to track the flow of execution with just logs.
• Proper debugging tools offer features like breakpoints, stepping through code, and inspecting variables. These make finding and fixing bugs much easier.

How to Add a Debugger to Debug Your Code

While console.log() is commonly used, it's not the most efficient for complex debugging tasks. Instead, you can use the V8 Inspector in NodeJS.

Steps for debugging in Node

Step 1: Write the following code in the terminal window as shown below:

node --inspect-brk filename.js

Step 2: Open your Chrome browser and write inspect as shown below

Step 3: Now click on Open Dedicated DevTools for Node.

Step 4: Now, click on the NodeJS icon. The terminal will show the following message:

Step 5: Other tools to help launch a DevTools window:

june07.com/nim
github.com/jaridmargolin/inspect-process
github.com/darcyclarke/rawkit

Suggested Quiz

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5 Questions

Which of the following is considered an inefficient and messy way to debug NodeJS applications, especially for complex scenarios?

• A

  Using the V8 Inspector

• B

  Using console.log()

• C

  Setting breakpoints

• D

  Using Chrome DevTools

Explanation:

The provided text states that beginners often use console.log() for debugging, but it "can become messy and inefficient" and "is not ideal for complex debugging scenarios" because it clutters the code and makes it hard to track the flow of execution.

To start the NodeJS debugger using the V8 Inspector for a file named app.js, what is the correct command to run in the terminal?

• A

  node --inspect-brk app.js

• B

  node debug app.js

• C

  node start --debugger app.js

• D

  node --dev-tools app.js

Explanation:

The text explicitly provides the command node --inspect-brk filename.js as the first step for debugging in Node. The other options are not the correct syntax for launching the V8 Inspector

What is a key benefit of using a proper debugging tool (like the V8 Inspector) over just console.log()?

• A

  It automatically fixes all bugs in the code.

• B

  It offers features like breakpoints and the ability to inspect variables

• C

  It is the only way to view output from a NodeJS application

• D

  It makes the application run faster during execution

Explanation:

The text highlights that "Proper debugging tools offer features like breakpoints, stepping through code, and inspecting variables," which makes finding and fixing bugs much easier than relying solely on console.log()

What is the primary purpose of the ANSI escape code `\x1b[0m`?

• A

  To set the text color to white

• B

  To set the text color to black

• C

  To highlight the text

• D

  To reset the text color to the default

Explanation:

This code is a reset command that returns the console's text formatting to its default state, removing any applied colors or styles.

Which of the following describes the correct first step for using the 'chalk' library to change console font color?

• A

  Install the library via npm

• B

  Run `npm start` in the terminal

• C

  Call the built-in `console.color()` method

• D

  Use the 'require' keyword to import it

Explanation:

The first step listed in the provided text for using the Chalk library is to install it via npm using the command `npm install chalk`.

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