Debugging is an essential part of the development process, and having the right tools can make a significant difference in your productivity. Visual Studio Code (VS Code) is a powerful editor that, combined with the Chrome Debugger, can help you efficiently debug your Next.js applications. In this blog, I’ll walk you through the steps to set up and attach the Chrome debugger to VS Code for debugging a Next.js application.

Prerequisites

Before we start, ensure you have the following installed:

1. Node.js
2. VS Code
3. Google Chrome
4. A Next.js application (you can create one using npx create-next-app)

Step 1: Install the Debugger for Chrome Extension

First, you’ll need to install the Debugger for Chrome extension in VS Code.

1. Open VS Code.
2. Go to the Extensions view by clicking on the Extensions icon in the Activity Bar on the side of the window or by pressing Ctrl+Shift+X.
3. Search for Debugger for Chrome.
4. Click Install.

Step 2: Create a Launch Configuration

Next, you’ll create a launch configuration that tells VS Code how to start Chrome with your Next.js application.

1. Open your Next.js project in VS Code.
2. Go to the Debug view by clicking on the Debug icon in the Activity Bar or by pressing Ctrl+Shift+D.
3. Click on the gear icon to open the launch.json file.
4. Add the following configuration to the launch.json file:

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Next.js: Chrome",
      "type": "chrome",
      "request": "launch",
      "url": "<http://localhost:3000>",
      "webRoot": "${workspaceFolder}",
      "breakOnLoad": true,
      "sourceMaps": true,
      "trace": true,
      "sourceMapPathOverrides": {
        "webpack:///./~/*": "${workspaceFolder}/node_modules/*",
        "webpack:///./*": "${workspaceFolder}/*",
        "webpack:///*": "*",
        "webpack:///src/*": "${workspaceFolder}/src/*"
      }
    }
  ]
}

This configuration tells VS Code to launch Chrome and attach the debugger to your Next.js application running on http://localhost:3000.

Step 3: Start Your Next.js Application

Before you can start debugging, you need to start your Next.js application.

1. Open a terminal in VS Code by pressing `Ctrl+“.
2. Run npm run dev to start your Next.js application in development mode.

Your application should now be running at http://localhost:3000.

Step 4: Start Debugging

With your application running and your launch configuration in place, you can start debugging.

1. Go to the Debug view in VS Code.
2. Select Next.js: Chrome from the configuration dropdown.
3. Click the green play button to start the debugger.

VS Code will launch a new instance of Chrome and attach the debugger to it. You can now set breakpoints in your code by clicking in the gutter next to the line numbers.

Step 5: Debugging Features

Here are some key features you can use while debugging:

• Breakpoints: Set breakpoints in your code where you want the execution to pause.
• Watch: Monitor variables and expressions.
• Call Stack: View the call stack to see the path your code took to reach the current breakpoint.
• Variables: Inspect variables in the current scope.
• Console: Use the Debug Console to evaluate expressions and execute code.

Conclusion

By following these steps, you can set up and attach the Chrome debugger in VS Code to debug your Next.js applications effectively. This setup allows you to leverage the powerful debugging features of both VS Code and Chrome, making your development process more efficient.

Happy debugging!