Tutorial: Debugging TypeScript Applications in VS Code

1. Introduction

The main goal of this tutorial is to equip you with the knowledge and techniques needed to debug TypeScript applications using Visual Studio Code (VS Code). You'll learn how to use various debugging tools such as breakpoints, console logs, and the step-through code feature.

By the end of this tutorial, you will be able to:
- Understand how to use VS Code for debugging TypeScript applications.
- Set breakpoints and step through your code.
- Use console logs for debugging.

Prerequisites: Basic understanding of TypeScript and VS Code.

2. Step-by-Step Guide

Concept: Debugging in VS Code

Debugging is the process of identifying and fixing errors in your code. VS Code provides a built-in debugging tool that simplifies this process. It allows you to set breakpoints, step through your code, and check the values of variables during runtime.

Setting Breakpoints

Breakpoints are the most common type of debugging. They allow you to pause your code execution at specific lines.

let x = 10; // Set a breakpoint here to watch the value of x
x *= 2;
console.log(x);

In VS Code, you can set a breakpoint by clicking to the left of the line number where you want to pause execution.

Using Console Logs

Another common debugging technique is to log information to the console. This can help to check the state of your application at specific points.

console.log("This is a basic console log."); // This will output the string to the console

Stepping Through Code

Stepping through your code allows you to move through your code one line at a time, examining the state of your application as it runs.

In VS Code, when your code is paused at a breakpoint, you can use the step over, step into, and step out buttons in the debugging toolbar to step through your code.

3. Code Examples

Example 1:

let x = 10;
x *= 2;
console.log(x); // Output: 20

Example 2:

for (let i = 0; i < 5; i++) {
  console.log(i); // Outputs: 0, 1, 2, 3, 4
}

4. Summary

In this tutorial, you've learned how to debug TypeScript applications in VS Code using breakpoints, console logs, and stepping through code. Further, you could practice these techniques by debugging some small applications.

5. Practice Exercises

1. Create a TypeScript application that calculates the factorial of a number. Debug the application to ensure it works correctly.

2. Create a TypeScript application that sorts an array of numbers in ascending order. Use breakpoints and console logs to debug the application.

Solutions

1. Here is a simple solution for the factorial problem:

function factorial(n: number): number {
  if (n === 0) {
    return 1;
  } else {
    return n * factorial(n - 1);
  }
}

console.log(factorial(5)); // Output: 120

1. Here is a simple solution for the sorting problem:

let arr = [5, 7, 2, 4, 1];
arr.sort((a, b) => a - b);
console.log(arr); // Output: [1, 2, 4, 5, 7]

Remember, the key to becoming proficient at debugging is practice. Keep building and debugging applications to improve your skills.