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Learn the best practices to manage loader visibility during data fetching in JavaScript using the Fetch API and async/await.
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This video is based on the question https://stackoverflow.com/q/72386863/ asked by the user 'Abhishek Purohit' ( https://stackoverflow.com/u/5866707/ ) and on the answer https://stackoverflow.com/a/72389716/ provided by the user 'Taurz' ( https://stackoverflow.com/u/19107625/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Show and Hide a Loader While Using Fetch in JavaScript

When developing applications that fetch data from APIs, it's crucial to provide visual feedback to users. A loader (or spinner) is an excellent way to inform users that a process is running in the background. This way, users understand that the application is responding, even when there's no immediate visual update. However, you might run into issues where the loader disappears too quickly, misleading the user regarding the fetch status. Let’s discuss how to implement a loader effectively in your JavaScript fetch calls.

The Problem

Imagine you're accessing an API using JavaScript's Fetch function, and you want to show a loader while the data is being fetched. Here's a common scenario you might encounter:

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

In this code snippet, the loader is supposed to display while the data is being fetched. However, you might notice that the loader only appears for a split second, disappearing before the fetch has completed. This situation can arise for several reasons, leading to a poor user experience.

Solution: Using try-catch-finally with async/await

One effective way to improve loader management during asynchronous operations is to use a try-catch-finally structure inside your async functions. This ensures that the loader remains visible until you have either fetched the data successfully or encountered an error.

Step-by-Step Solution

Show the Loader Before Fetching: Immediately display the loader when the fetch process begins.

Use try-catch for Error Handling: This allows you to catch any errors during data fetching without breaking the flow of your code.

Hide the Loader in the Finally Block: Regardless of whether the fetch was successful or failed, ensure that the loader is hidden afterward.

Here’s the revised code using these concepts:

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

Explanation of Changes

Loader Management: The loader is shown immediately before the fetch call and kept visible until the finally block executes, ensuring it stays on-screen during loading times.

Structured Error Handling: Using try-catch means that if the fetch fails, you'll handle the error gracefully, providing feedback without crashing the application.

Clear Console Logs: Optional console logs can help track the fetch process during debugging and ensure everything operates as expected.

Conclusion

Implementing a loader during API calls using JavaScript's Fetch functionality doesn't just enhance user experience—it could be vital for usability. By following the steps outlined above and maintaining structured control over your asynchronous operations, you can ensure that your applications remain user-friendly and informative.

Feel free to apply these techniques in your projects to improve your data fetching processes today!