Solving Angular 11 Firebase Server-side Rendering Issues: Overcoming Infinite Loading State

Learn how to tackle the `infinite loading` issue in your Angular 11 app when implementing `server-side rendering` with Firebase, including a practical workaround that keeps your app responsive.
---
This video is based on the question https://stackoverflow.com/q/65388261/ asked by the user 'Julien' ( https://stackoverflow.com/u/850438/ ) and on the answer https://stackoverflow.com/a/65388376/ provided by the user 'Julien' ( https://stackoverflow.com/u/850438/ ) 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: Angular 11 Firebase Server-side rendering infinite loading / pending

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/licensing
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Solving Angular 11 Firebase Server-side Rendering Issues: Overcoming Infinite Loading State

When building applications with Angular 11 and integrating Firebase, developers often take advantage of server-side rendering (SSR) for pre-rendering their Angular pages on the server. However, many have encountered issues, particularly the infinite loading or pending queries that leave users staring at an incomplete page. In this guide, we'll dive into identifying the root of this problem and how to implement a robust solution.

Understanding the Problem

You have a well-functioning Angular 11 application in client-side rendering mode (CSR) using Firebase. However, as soon as you switch to SSR, you encounter several issues:

Hanging Express Server: Your server becomes unresponsive.

Pending Queries: Client-side displays a persistent loading state or a timeout error, preventing users from seeing rendered results.

This problem typically surfaces when executing Firebase queries, which seem to hang indefinitely in SSR mode.

The Code That Works in CSR

Your original code to query a Firebase Firestore collection works seamlessly when SSR is not involved:

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

Locating the Source of the Problem

After extensive debugging, it was discovered that the specific Firebase query in use was the source of the hang-up. Upon switching to SSR, the execution of this code fails to complete, leading to an unresolved state.

Key Observations

Closing the Observable: Using a sensible approach, like take(1) should theoretically make sense for non-observing queries, yet this leads to the server hanging.

Firebase Behavior: It appears that when executing valueChanges() followed by a take(2), the hang issue disappears, leading us to believe there is a bug somewhere within the Firebase stack.

The Workaround Solution

To solve the infinite loading issue, we propose the following workaround:

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

Why This Works

The use of valueChanges() allows you to receive updates about the documents in the collection.

The take(2) ensures that you only subscribe to the observable twice, preventing the hanging behavior while still fetching the data needed for rendering.

Alternative Approaches That Fail

Using take(1) with valueChanges():

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

Interestingly, this seemingly logical approach fails to execute properly during SSR, resulting in an unresolved state.

Employing Promises:
Trying to use Firebase with promises also leads to hanging requests, causing frustration and delays.

Conclusion

Switching to SSR can be a beneficial optimization for Angular applications utilizing Firebase, but it comes with its own set of challenges. By identifying the root cause of the hanging requests and adopting a valueChanges() approach with take(2), you can achieve a responsive server-side rendering setup without facing infinite loading issues.

If you're encountering similar issues, we hope this workaround aids you in overcoming the challenges and bolsters the performance of your Angular 11 app integrated with Firebase.

Happy coding!

Видео Solving Angular 11 Firebase Server-side Rendering Issues: Overcoming Infinite Loading State канала vlogize