How to Resolve the Infinite Loop Issue in Angular 8's canActivate Routing

Discover how to fix the `endless redirection` problem in Angular 8's canActivate when navigating routes based on user roles.
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This video is based on the question https://stackoverflow.com/q/61034578/ asked by the user 'Michael Winther' ( https://stackoverflow.com/u/917112/ ) and on the answer https://stackoverflow.com/a/66121559/ provided by the user 'Melissa Heying' ( https://stackoverflow.com/u/14502997/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Troubleshooting Infinite Loop in Angular 8's canActivate

Angular is a robust framework that allows developers to create complex and dynamic single-page applications. However, sometimes developers encounter unexpected issues during routing, particularly when implementing canActivate guards for route protection. A common issue is experiencing an infinite loop when redirecting users based on their roles after login.

The Problem

In the scenario presented, after a user logs in, the application is supposed to redirect them to either an admin dashboard or a user component based on their assigned role. However, instead of correctly routing the user on their first attempt, the code results in an infinite loop, causing the application to repeatedly alert the user and fail to fetch the intended route URLs.

Key Observations:

The route variable in canActivate is empty during the first invocation, causing conflicts in routing logic.

The alert indicating navigation is repeatedly triggered, indicating that the expected state of the application is not being reached.

Understanding the Code

Here’s a quick run-down of the relevant files before implementing the solution:

1. App-routing.module.ts

The routing module defined in the application handles the path redirection based on user roles.

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2. Redirect-guard.service.ts

This guard handles navigation based on user roles stored in local storage.

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Important Notes:

The alert is triggered infinitely, suggesting a flaw in handling path states.

The AuthGuardService is never reached due to the looping problem.

The Solution

Through troubleshooting, it became clear that the issue was related to module imports and routing configurations. Here’s how to fix it:

Step 1: Adjust Module Imports

Make sure the AuthModule is imported before the AppRoutingModule in your app.module.ts. This adjustment is crucial for allowing the router to recognize paths correctly.

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Step 2: Optimize Routing Configuration

If additional routing files exist (like auth-routing.module.ts), always check for conflicts or overrides of paths. For instance, ensure wildcard routes:

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Moving such overrides into the appropriate routing module can solve potential conflicts.

Conclusion

The infinite loop in canActivate is primarily due to improper module imports and unnecessary complexity introduced by multiple routing files. By ensuring the AuthModule loads correctly and refining the routing logic, you can smooth out the user navigation experience.

Remember, always verify your routing sequences, module imports, and ensure that your authentication guards are functioning as expected.

Happy coding!

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