Скачать или смотреть Solving the NGRX Error Handling Dilemma: Success Before Failure in Angular Apps

Learn how to manage error handling effectively in NGRX within your Angular applications to ensure correct user notifications. Discover the right approach to dealing with failures without unnecessary complexity.
---
This video is based on the question https://stackoverflow.com/q/70817693/ asked by the user 'Snipered' ( https://stackoverflow.com/u/8510759/ ) and on the answer https://stackoverflow.com/a/70838418/ provided by the user 'Eddie Paz' ( https://stackoverflow.com/u/364183/ ) 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: NGRX returns success before throwing error

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
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.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Solving the NGRX Error Handling Dilemma: Success Before Failure in Angular Apps

In Angular applications, particularly when using the NGRX state management library, developers might encounter a frustrating issue: receiving a success message even when there's an underlying error. This can be particularly challenging when trying to provide users with proper feedback through notifications. Let’s delve into a common scenario where an exception is thrown in a service and examine how to appropriately handle it in NGRX effects.

The Problem

Imagine you have a service that attempts to save a business object to the database. If the operation fails, you want to catch this error and display a corresponding toast notification to the user. However, instead of seeing an error notification, you receive a success message followed by the error itself appearing only in the console. This can lead to confusion and a poor user experience.

What Should Happen

When the operation fails, the user should receive an "Error" toast on the frontend instead of a success message.

The application should handle errors gracefully, providing feedback that is accurate to the user's action.

Understanding the Current Code Structure

Let’s break down the provided code snippets and identify where adjustments are needed:

1. Service Implementation

In the service, the method looks like this:

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

Issues in the Service

The current implementation unnecessarily catches the error only to throw it again. This adds complexity without any benefits.

2. Effect Implementation

In the effect, the current structure is as follows:

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

Issues in the Effect

Wrapping this.businessService.saveBusiness(business) in of() creates an unnecessary observable.

The error catching mechanism might not provide details about the error, which can be helpful for error handling notifications.

The Solution

Step 1: Update the Service Method

Remove the unnecessary error handling in the service. The revised method should directly return the observable from the add() operation:

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

Step 2: Refine the Effect

Modify the effect to handle the observable in a straightforward manner, directly utilizing the service method without wrapping it in of():

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

Benefits of the Revised Solution

By removing unnecessary complexity, you streamline the process and make it easier to read and maintain.

Proper error handling ensures that the failure notification is correctly triggered when an error occurs, leading to a better user experience.

Implementation of Notifications

Your component that handles notifications should remain as is, as it correctly subscribes to both success and failure actions:

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

Conclusion

In summary, handling errors effectively in your NGRX state management can significantly enhance user experience. By simplifying the error handling process in your service and effect, you ensure that users receive accurate and timely feedback regarding their actions. Implementing these changes not only resolves the issue you faced but also prepares your application for more robust error handling in the future. Prioritize clarity and simplicity in your code to maintain efficiency and improve maintainability.