Introduction

In this tutorial, we will dive into debugging Node.js applications using Visual Studio Code (VS Code). Debugging is the process of identifying and fixing errors in your code, and it's a vital part of the software development process. By the end of this tutorial, you'll understand how to use VS Code's built-in debugging tools to streamline and enhance your debugging process.

What you will learn
- Configuring VS Code for debugging Node.js applications
- Setting breakpoints and stepping through your code
- Inspecting variables and watching expressions

Prerequisites
- Basic understanding of Node.js
- VS Code installed on your system
- A Node.js application to debug

Step-by-Step Guide

1. Configuring VS Code for Debugging

   • Open your Node.js project in VS Code.
   • Click on the Debugging icon in the Activity Bar to switch to the Debug view.
   • In the Debug view, click on the gear icon to open the .vscode/launch.json file. This file is used to configure VS Code's debugging behavior.
   • In the launch.json file, select "Node.js" from the environment dropdown.

2. Setting Breakpoints

   • Open the file where you want to set a breakpoint.
   • Click in the gutter to the left of a line number to set a breakpoint on that line.

3. Starting a Debugging Session

   • Go back to the Debug view in VS Code.
   • Click the green play button at the top to start a debugging session.

4. Inspecting Variables and Watching Expressions

   • When your code hits a breakpoint, you can inspect variables in the Variables pane in the Debug view.
   • You can also watch expressions in the Watch pane.

Code Examples

Consider the following example of a simple Node.js application:

// app.js
let counter = 0;

function incrementCounter() {
  counter++;
  console.log(`Counter: ${counter}`);
}

setInterval(incrementCounter, 1000);

You could set a breakpoint on the line counter++;, start a debugging session, and watch the counter variable to see it increment each second.

Summary

In this tutorial, you've learned how to configure VS Code for debugging Node.js applications, how to set breakpoints and start debugging sessions, and how to inspect variables and watch expressions during a debugging session.

For further learning, you might explore conditional breakpoints, logpoints, and other advanced debugging features in VS Code.

Practice Exercises

1. Exercise 1: Create a simple Node.js application and set a breakpoint. Start a debugging session and observe the program's execution.

2. Exercise 2: In your Node.js application, add a variable and watch its value change in the Watch pane during a debugging session.

3. Exercise 3: Experiment with conditional breakpoints and logpoints in your application.

Remember, practice is the key to mastering any skill, so make sure to practice these exercises and experiment with the debugging features in VS Code. Happy coding!