Скачать или смотреть How to Prevent Previous Data from Disappearing Before New Data is Fetched in Your Web App

Discover how to improve your web app's user experience by preventing old data from disappearing before new data is loaded. Read on for a step-by-step solution.
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This video is based on the question https://stackoverflow.com/q/67502445/ asked by the user 'vdmclcv' ( https://stackoverflow.com/u/13426925/ ) and on the answer https://stackoverflow.com/a/67502644/ provided by the user 'R44' ( https://stackoverflow.com/u/5724095/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Introduction

If you're developing a web application that fetches data from an API, you might encounter a tricky situation: when you initiate a data fetch, the previous data disappears before the new data is fully loaded. This can create a jarring experience for users, as the page seems to flicker and visual information is momentarily absent. In this post, we’ll delve into how you can prevent this from happening and ensure a smooth transition when fetching data.

The Problem

In your app, you have a simple button that, when clicked, tells the browser to retrieve new information from a remote API. This process looks something like this:

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

However, when the above code runs, the old data vanishes immediately due to the button's default behavior, which can lead to a poor user experience while waiting for the new data to load.

Solution

To solve this issue, you need to modify your event handler in a way that prevents the old data from disappearing until the new data is ready to be displayed. The key to this is to avoid the default postback behavior that the button click triggers.

Step-by-Step Instructions

Here’s how you can modify your code to keep the old data visible until the new one is ready:

1. Use stopPropagation() Method

Adding the e.stopPropagation() method to your click event handler is crucial. It prevents the click event from bubbling up to parent elements and ensures the default behavior, which causes the old data to disappear, does not occur.

2. Updated Code Example

Here is the updated code snippet with stopPropagation() included:

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

3. How It Works

e.preventDefault();: This line stops the button from executing its default behavior that affects the page state.

e.stopPropagation();: This prevents the event from impacting parent elements, further controlling how your application responds to the button click.

By implementing these changes, you ensure that while you are fetching new information, users can still see the previous data, leading to a much better user experience and presentation.

Conclusion

User experience is paramount in web development. By making a few simple adjustments to your event handling in JavaScript, you can ensure that your application remains smooth and visually coherent while data is being fetched. Remember to always consider how user interactions will affect the display of information in your application, and take steps to mitigate any disruptions.

Now, go ahead and apply these tips to your web app, and see how it enhances the way users interact with your content!