Fixing the Chrome Debugger Issue in Angular Unit Tests

Описание: Struggling with debugging unit tests in your Angular app? Discover how to resolve the `Chrome debugger` source map issues and get back to effective debugging!
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This video is based on the question https://stackoverflow.com/q/63393033/ asked by the user 'Wouter van Koppen' ( https://stackoverflow.com/u/1582709/ ) and on the answer https://stackoverflow.com/a/63618069/ provided by the user 'Wouter van Koppen' ( https://stackoverflow.com/u/1582709/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Fixing the Chrome Debugger Issue in Angular Unit Tests: A Practical Guide

Debugging is an essential part of the development process, especially in Angular applications where unit tests play a key role in ensuring that your code works as expected. However, a common issue developers face is that the Chrome debugger does not behave as expected when stepping into production code from unit tests. This guide will explore this issue in detail and provide you with a straightforward solution to make unit test debugging work seamlessly in your Angular application.

The Problem: Chrome Debugger Stepping into the Wrong Lines

When you run your unit tests using the ng test command in an Angular 8 application, you may notice that the Chrome debugger fails to step into the correct lines of your production code. Instead, it might lead you to:

Empty lines and declarations in code

Unrelated sections of the codebase

Incorrect lines altogether

This confusing behavior often arises due to problems with the source maps, which are responsible for mapping the minified and compiled code back to the original source code. A common culprit in this situation could be the configuration settings in your package.json file, particularly the way you trigger your unit tests and generate code coverage.

The Solution: Adjusting Your package.json Configuration

To resolve this issue, you need to make adjustments to your package.json configuration regarding how you run your tests and generate coverage reports. Specifically, the key takeaway is to separate the test commands. Here’s how you can do it:

Step 1: Modify Your Scripts in package.json

In your package.json, you likely have a script that looks something like this for running your tests:

[[See Video to Reveal this Text or Code Snippet]]

This configuration attempts to run tests while simultaneously generating code coverage. Unfortunately, the --code-coverage flag can interfere with the correct generation of source maps, causing debugger issues.

Modify it to:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Run Your Tests with the Correct Command

Now, whenever you want to run your unit tests and debug through Chrome, simply use the command:

[[See Video to Reveal this Text or Code Snippet]]

This will allow you to add breakpoints in Chrome and step through your unit test and production code correctly. When you need code coverage reports, you can run:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By separating your unit test execution command from your code coverage command, you can effectively resolve the Chrome debugger stepping issues in Angular applications. Debugging should be a smooth and helpful process rather than a frustrating struggle. With the solution provided in this guide, you can get back to developing robust Angular applications with the confidence that your tests will behave as expected.

Whether you’re a beginner or a seasoned developer, it’s crucial to ensure that your debugging tools function correctly to streamline your workflow. Follow these steps to ensure smooth sailing in your unit test debugging journey!

If you have any further questions or run into issues, feel free to reach out in the comments below. Happy coding!