Visual Studio Code Debugging

Introduction to Debugging in VS Code

Debugging is a crucial part of the software development lifecycle. It allows you to identify and fix errors (bugs) in your code. Visual Studio Code (VS Code) provides a powerful and flexible debugging experience with built-in support for many programming languages and runtime environments.

VS Code's debugger integrates seamlessly with your workflow, enabling you to set breakpoints, step through code, inspect variables, examine the call stack, and much more, all without leaving your editor.

Getting Started with Debugging

To start debugging, you typically need:

• Your application code.
• A runtime environment (e.g., Node.js, Python, .NET).
• A debugger extension (often built-in or easily installable).
• A launch configuration to tell VS Code how to start your application and attach the debugger.

You can access the debugger by clicking on the "Run and Debug" icon in the Activity Bar on the left side of VS Code. This will open the Debug view.

Key Debugging Windows

The Debug view provides several essential panels:

• Variables: Shows the current values of variables in scope.
• Watch: Allows you to monitor specific expressions or variables.
• Call Stack: Displays the sequence of function calls that led to the current execution point.
• Breakpoints: Lists all breakpoints you've set.

Breakpoints

Breakpoints are essential for pausing your program's execution at specific lines of code. In VS Code, you can set a breakpoint by clicking in the gutter to the left of a line number.

Launch Configurations (launch.json)

VS Code uses a file named launch.json to store your debugging configurations. This file, located in a .vscode folder in your workspace, defines how to launch and debug your application.

When you click "Run and Debug" for the first time, VS Code will prompt you to create a launch.json file and help you select the appropriate environment.

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Launch Program",
            "type": "node",
            "request": "launch",
            "program": "${workspaceFolder}/app.js",
            "cwd": "${workspaceFolder}",
            "console": "integratedTerminal",
            "sourceMaps": true
        }
    ]
}
            

Key properties in a launch configuration include:

• name: A friendly name for the configuration.
• type: The debugger type (e.g., node, python, coreclr).
• request: Either launch (start a new process) or attach (connect to an existing process).
• program: The entry point of your application.

Debugging Different Languages

VS Code's debugging capabilities are extended through extensions. Official extensions are available for popular languages:

• Node.js (JavaScript/TypeScript): Built-in.
• Python: Via the Python extension.
• .NET (C#/F#/VB.NET): Via the C# extension.
• Java: Via the Extension Pack for Java.
• PHP: Via the PHP Debug extension.

Ensure you have the appropriate language extension installed for the best debugging experience.

Advanced Debugging Features

VS Code offers advanced debugging capabilities such as:

• Debugging remote applications: Connect to debug processes running on other machines or in containers.
• Debugging web applications: Debug JavaScript running in the browser.
• Attaching to running processes: Debug an application that is already running.
• Exception handling: Configure how exceptions are handled during debugging.
• Step Over, Step Into, Step Out: Control code execution flow.
• Console evaluation: Execute code snippets in the context of the running application.