Скачать или смотреть How to Show a Loading Overlay on Images in React Before They Update

Discover how to maintain the previous image in React while showing a `Loading...` overlay before the new image loads, ensuring a smoother user experience.
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This video is based on the question https://stackoverflow.com/q/75687549/ asked by the user 'Siri' ( https://stackoverflow.com/u/12267640/ ) and on the answer https://stackoverflow.com/a/75721276/ provided by the user 'Alex Nikulin' ( https://stackoverflow.com/u/5138198/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Show a Loading Overlay on Images in React Before They Update

When working with image components in React, particularly those that update frequently, one common problem arises: how to manage the visibility of the image while a new one is loading. If you've experienced your image disappearing and only reappearing after the new image has been fetched, you're not alone. Let's dive into a straightforward solution to maintain the old image's presence while signaling to users that a new version is on its way.

The Problem

Imagine you have an image that refreshes every minute. As the timer runs out and a new image is fetched, the existing image suddenly disappears. Not only is this jarring for users, but it can also create an unpolished experience. Instead, we want to:

Keep the previous image visible.

Show a Loading... overlay until the new image is loaded.

Transition seamlessly from the old to the new image without abrupt changes.

The Solution Overview

To tackle this issue, we can utilize React's useEffect hook to preload the new image, keeping track of loading states using the useState hook. Here’s how you can implement this:

Step-by-Step Implementation

Set Up State Variables:
We'll need two state variables: one for tracking the loading state and another to hold the cached image URL.

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

Fetching and Preloading the New Image:
Use the useEffect hook to trigger when the source URL (src) changes. Within this effect:

Set the loading state to true.

Create a new Image instance to preload the new image.

When the image has loaded, update the cached image URL and set a short delay before the Loading... text disappears.

Here’s what the code looks like:

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

Returning the JSX:
In the return statement, you’ll render the image with an overlay that displays Loading... while the new image is being fetched:

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

Putting It All Together

Combining all these elements results in a cohesive component that handles image loading more gracefully. Here’s the full component for clarity:

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

Conclusion

By following this guide, you'll successfully manage image loading in your React applications. Not only will you enhance the user experience by providing feedback during loading, but you'll also maintain visual continuity for images that update frequently. With just a few tweaks and the power of React's hooks, a smoother transition can be achieved effortlessly.

Keep experimenting with your image components to refine the loading experience even further!