debugging
Alright, let’s dive into debugging TypeScript applications in VS Code. This skill is invaluable when troubleshooting issues and making sure our code behaves as expected. We’ll break it down into a few steps:
Step 1: First, navigate to your tsconfig.json file. In the emit section, enable the “source map” feature. A source map is a file that helps map each line of TypeScript code to its corresponding JavaScript code. This is primarily for debuggers and not meant for human understanding.
Step 2: After enabling source maps, recompile your code. You’ll notice a new file in your folder, named index.js.map. This is your source map file.
Step 3: Let’s make debugging more interactive. Open index.ts and add some logic. For instance, you can insert a breakpoint by clicking on the line number. Breakpoints pause code execution when reached.
Step 4: Access the debug panel and create a launch.json file. From the dropdown, select node.js. This file configures VS Code for debugging. It specifies that we’ll use Node.js to run and debug our program.
Step 5: Add a pre-launch task setting in launch.json. Set it to "tsc build - tsconfig.json". Pay attention to the spaces; they’re crucial. This tells VS Code to use the TypeScript compiler to build your application using the specified configuration.
Step 6: Now, go back to index.ts. To start debugging, open the debug panel and click on “Launch Program” or use the shortcut F5.
Step 7: Your program starts, and execution halts at the breakpoint. In the debug panel, you have various tools:
- Step Over (F10): Execute one line of code.
- Step Into: Useful for functions.
- Step Out: Useful for leaving functions.
- Restart: Restart the debugging session.
- Stop: Terminate debugging.
Step 8: On the left, under “Variables,” you can see detected variables. As you step through the code, watch these values change. If you don’t see a variable, you can add it to the “Watch” window.
Step 9: As an example, add a console.log statement to see its effect during debugging. Start the debugging session with F5, and use F10 to step through lines.
Debugging in VS Code is a powerful tool to pinpoint issues and understand your code’s behavior step by step.
Once you’re done debugging, simply stop the debugging session.
This concludes our debugging section. In the next section, we’ll delve deeper into TypeScript.
I’ve restructured the text for better readability and comprehension. It now provides clear steps and explanations for debugging TypeScript applications in VS Code.