Solving the authRequired Meta Issue in Vue.js with Firebase Authentication

Описание: Discover how to effectively manage route authentication in your Vue.js admin dashboard using Firebase. Learn about the common pitfalls and the best solutions to avoid displaying unauthorized content.
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This video is based on the question https://stackoverflow.com/q/66706442/ asked by the user 'Tom Evertzen' ( https://stackoverflow.com/u/8839499/ ) and on the answer https://stackoverflow.com/a/66851957/ provided by the user 'maxim' ( https://stackoverflow.com/u/11915216/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Page with the authRequired meta still gets shown for a split second even when no one is logged in on Firebase

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The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

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Solving the authRequired Meta Issue in Vue.js with Firebase Authentication

Feeling stuck with a persistent issue in your Vue.js project? You're not alone! Many developers encounter challenges when setting up route authentication, especially with Firebase. If you've faced the problem of unauthorized pages appearing briefly before redirecting to the login screen, this guide is here to help you out!

Understanding the Problem

As a part of your admin dashboard development, you've set up routes in Vue Router and marked certain routes (like your Dashboard) as requiring authentication with meta: { requiresAuth: true }. However, you notice that when attempting to access the /dashboard route while logged out, it displays the dashboard for a moment before redirecting to the login page.

This issue arises due to the way the authentication state is checked. Let's dive deeper into why this happens and how to resolve it.

The Root Cause

The main issue lies in the use of the auth.onAuthStateChanged method. This method adds an event listener that runs asynchronously when the authentication state changes, which means that by the time your router checks if a user is logged in, it may have already displayed the protected page before the check completes.

Key Points to Note:

Async Behavior: The check for logged-in status happens asynchronously.

Immediate Rendering: The web page attempts to render the Dashboard page before the authentication check is complete.

Implementing a Solution

To solve this issue, we need to implement a synchronous check for the user's authentication state. Here’s a clear and efficient approach to fix the problem:

Step 1: Create a Local User Variable

Start by defining a variable to store the user state. Place this outside the router setup to maintain its value regardless of the route.

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

Step 2: Modify the Router Guard

Next, we adjust the beforeEach hook in the router to check the local user variable instead of relying solely on the asynchronous event listener.

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

Why This Works

Immediate Access: Now, you are checking the authentication state synchronously, which means the user variable either holds the logged-in user or null right when the router checks it.

No Flickering: This eliminates any flicker of the Dashboard page, providing a seamless user experience.

Conclusion

By implementing a local user variable to store the authentication state and utilizing it for your route guard, you can effectively prevent unauthorized access to protected routes without the split-second display of restricted content. This setup not only resolves the immediate issue but also enhances the overall user experience of your Vue.js application.

Let me know if you run into any other issues or if further clarification is needed—I'm here to help! Happy coding!