Скачать или смотреть Handling Network Errors with the Browser Fetch API

Learn how to effectively manage network error handling in JavaScript using the Fetch API. Improve your web application's resilience by detecting down networks and responding appropriately.
---
This video is based on the question https://stackoverflow.com/q/73977372/ asked by the user 'Igor Shmukler' ( https://stackoverflow.com/u/5800846/ ) and on the answer https://stackoverflow.com/a/73981606/ provided by the user 'Igor Shmukler' ( https://stackoverflow.com/u/5800846/ ) 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: Detecting network is down from browser Fetch API

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.
---
Handling Network Errors with the Browser Fetch API: A Comprehensive Guide

In today's web applications, managing network requests effectively is crucial. The Fetch API has become a standard for making these requests, but it can sometimes throw users off when it doesn’t handle errors as expected. A common issue that developers face is detecting when a network is down or unreachable, leading to unhandled promise rejections or confusing errors. In this guide, we’ll explore how to handle such network errors gracefully using JavaScript's Fetch API.

The Problem: Detecting Network Errors

You might have experienced this: your application makes a network request, but the fetch operation fails, not due to any response issue, but because the network itself is down. The default behavior of the Fetch API does not include throwing errors for network issues, which can leave developers puzzled. For example, if a network request fails, you might get an error message like "cannot read properties of undefined (reading 'status')", which is not helpful for the user.

The goal here is to adjust our utility function so that it can properly identify network errors and react accordingly by throwing a clear Failed to fetch error instead.

Solution Overview

The key adjustments involve modifying your existing request handling function and the error handling process. Here’s a step-by-step breakdown of the improved approach:

1. Updating the parseJSON Function

The parseJSON function should be updated to work asynchronously. This change allows it to handle the response.json() method correctly in an asynchronous context. Here’s how you do it:

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

2. Revising the checkStatus Function

Your checkStatus function can remain mostly the same. However, it’s essential to ensure it continues to throw an error for responses with a status that falls outside the 2xx range.

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

3. Handling Network Requests with Error Catching

The crux of the solution lies in the request function. Here, we can implement a try-catch block that will appropriately manage any errors that may occur during the fetch operation. Ensure that your function looks similar to this:

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

Conclusion

By implementing the adjustments laid out in this guide, you'll provide a better experience for users and create a more robust application. Handling network errors properly with the Fetch API not only improves error messages but also allows for better debugging and user feedback. Implement these changes to ensure your network requests are both efficient and informative.

Now it's time to put this into action. Start refining your fetch method and handle those network errors like a pro!