How to Debug Typescript Code Like a Pro

Are you tired of spending hours debugging your Typescript code, only to find a simple syntax error at the end? Do you want to become a seasoned developer who can debug like a pro? Look no further! In this comprehensive guide, we will take you through the ins and outs of debugging Typescript code like a pro.

Introduction

Debugging is a crucial part of the development process. It allows you to find and fix errors in your code, ensuring a smooth and functional application. Typescript, being a statically-typed language, offers significant advantages in terms of debugging like catching type-related errors at compile time. However, it can still be challenging to debug, especially for beginners. But worry not, by the end of this article, you'll be able to debug Typescript code like a pro!

Setting up your IDE for Typescript

The first step towards successful debugging is setting up your IDE correctly. There are various IDEs available for Typescript, such as Visual Studio Code, Webstorm, Atom, etc. Here are a few essential settings you would want to configure on your IDE to optimize your debugging experience.

Installing the Typescript compiler

Before setting up your IDE, you must have the Typescript compiler installed on your system. The simplest way to do this is by using npm (node package manager) to install Typescript globally on your local machine. Run the following command in your terminal to install Typescript:

npm install -g typescript

Configuring your IDE for Typescript

Different IDEs have their configurations for Typescript. Here's a brief overview of the settings you might want to tweak:

Visual Studio Code

Visual Studio Code, being the most popular IDE for Typescript, has fantastic built-in support for Typescript. Here are a few settings that might come in handy while debugging:

1. Debugging launch configuration: Visual Studio Code's launch configuration allows you to set up different debugging scenarios. You can set breakpoints, debug on Chrome, or debug remote servers by tweaking various debug settings.

2. tsconfig.json: This is the Typescript project configuration file that defines how Typescript should be compiled. Setting up the allowJs and sourceMap options can make your debugging experience smoother.

WebStorm

WebStorm, another popular IDE for Typescript, offers tight integration with the Typescript compiler. Here are a few settings that you might find useful in WebStorm:

1. Typescript Compiler Settings: In WebStorm's preferences, you can set up the Typescript Compiler settings according to your project requirements.

2. Debugging Configurations: WebStorm's debugging configurations allow you to set up different scenarios for debugging. You can debug on Chrome, Node.js, and even remotely through SSH.

Debugging Techniques

Now that you have set up your IDE, let's dive into the various debugging techniques that can make your life easier while debugging.

Console.log()

Your first line of defense while debugging is using console.log(). It is perhaps one of the most widely used debugging techniques for Typescript. It allows you to print variable values, function return values, and even objects to the console. Here is a simple example:

function add(a: number, b: number) {
  const sum = a + b;
  console.log(`The sum of ${a} and ${b} is ${sum}`);
  return sum;
}
add(3, 4); // Output: The sum of 3 and 4 is 7

Debugging with Breakpoints

Breakpoints are markers in your code where the debugger should stop. It is one of the most powerful debugging techniques in your arsenal. By setting breakpoints at specific lines, you can grasp the state of your application at that point. Here are a few ways to set breakpoints in your code:

Visual Studio Code

In Visual Studio Code, you can set breakpoints by clicking on the left margin of the editor. You will see a red dot indicating a breakpoint at that line. Alternatively, you can use the F9 key to set or remove breakpoints.

WebStorm

In WebStorm, you can set breakpoints by clicking on the left margin of the editor. You will see a blue circle indicating a breakpoint at that line. Alternatively, you can use the F8 key to set or remove breakpoints.

Once your breakpoints are in place, you can then run your code in the debugging mode. This will allow you to step through your code, line by line, and see how your code behaves. You can also view the state of your variables and modify them if required.

Debugging with the Debugger Statement

The debugger statement is a Typescript native way to set breakpoints in your code. By adding the debugger keyword anywhere in your code, the Typescript compiler will treat it as a breakpoint. This technique is particularly useful when you want to debug a specific block of code, and you don't want to set a persistent breakpoint. Here's how you can use the debugger statement in your code:

function add(a: number, b: number) {
  const sum = a + b;
  debugger;
  return sum;
}
add(3, 4);

Once you run this code in debugging mode, the Typescript compiler will stop execution at the line where the debugger statement is.

Debugging with Conditional Breakpoints

Conditional breakpoints are breakpoints that will only stop execution when a specific condition is met. It allows you to filter out specific scenarios, which reduces the number of times the debugger stops. Here is how you can set up a conditional breakpoint:

Visual Studio Code

In Visual Studio Code, you can add conditions to the breakpoint by right-clicking on the breakpoint marker and selecting "Edit breakpoint." Here, you can set up conditions based on the value of a variable or a particular expression.

WebStorm

In WebStorm, you can add conditions to the breakpoint by right-clicking on the breakpoint marker and selecting "Edit breakpoint" Here, you can set up conditions based on the value of a variable or a particular expression.

Once you set up your conditional breakpoint, the Typescript compiler will stop execution only when the specified condition is met.

Debugging with Chrome Developer Tools

Typescript offers an excellent integration with Chrome's Developer Tools. With Chrome's Developer Tools, you can live-edit your variables, watch expressions, and step through your code. Here is how you can use Chrome's Developer Tools:

1. Run your Typescript code with the --inspect flag : tsc --inspect <name-of-the-file>.ts

2. Open Chrome and go to the URL chrome://inspect.

3. Click on Open dedicated DevTools for Node and select your application.

4. Your Typescript code will now appear in the Sources tab. You can set up breakpoints here and start debugging!

Conclusion

Debugging Typescript may seem intimidating at first, but with the right tools and techniques, it can be a breeze. In this article, we've covered essential IDE settings, console.log(), breakpoints, the debugger statement, conditional breakpoints, and Chrome's Developer Tools. Armed with these techniques, you'll be able to nip bugs in the bud and deliver high-performing and well-functioning applications.

Now, what are you waiting for? Start debugging like a pro!

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