How to Manage State Asynchronously in Vanilla JavaScript with a Loading Indicator

Описание: Discover how to effectively manage asynchronous state in JavaScript by adding a `Loading` indicator that only appears after a delay when fetching data.
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This video is based on the question https://stackoverflow.com/q/62962825/ asked by the user 'Farid' ( https://stackoverflow.com/u/6946549/ ) and on the answer https://stackoverflow.com/a/62962868/ provided by the user 'Ross Mackay' ( https://stackoverflow.com/u/2760126/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Managing State Asynchronously in Vanilla JavaScript

In web development, fetching data from APIs is a common task. However, managing the user experience during these asynchronous operations can sometimes be challenging, especially when it comes to displaying loading states. In this guide, we will explore how to effectively manage loading states in vanilla JavaScript, ensuring a seamless experience for users on both fast and slow connections.

The Problem: Making Users Wait

When working with asynchronous calls, like fetching data from an API, you typically want to indicate to users that something is happening in the background. For example, if you are fetching a list of countries from a remote API, it’s ideal to show a loading message if the response takes a while. But what happens when your application is incredibly fast? In that case, the loading message might flicker on the screen for only a split second, which can be confusing for users.

Here’s how the initial approach worked:

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

While this method works effectively, it can lead to inconsistent user experiences based on network speeds. So how can we improve this?

The Solution: Introducing a Delay

To enhance the loading experience, we can utilize a setTimeout function to add a necessary delay. This way, the loading text will only appear if the data fetching takes longer than a specified time, such as one second. Let’s break it down into clear steps:

Step 1: Set Up the Timeout

First, we need to create a variable to hold the response. This allows us to check if the response is available after our timeout. Here’s how to modify our original function:

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

Step 2: Explanation of the Code

Variable Declaration: By declaring let response; at the beginning, we ensure it is in the scope of the timeout function.

Set Timeout: The setTimeout function checks if the response was received within one second. If not, the loading message is displayed.

Awaiting the Response: The await keyword halts the execution of the function until the Promise resolves. If the response is quick enough, the loading state does not get presented at all.

Error Handling: Always include error handling in asynchronous functions to manage any potential failures gracefully.

Conclusion: A Better User Experience

By implementing a loading state that only appears if the response takes longer than a second, we can enhance the user interface of our JavaScript applications. This approach provides a cleaner, more user-friendly interaction with your web applications and helps to manage users' expectations during data fetching operations.

Now you're equipped to manage state asynchronously in vanilla JavaScript like a pro! Whether your users are on fast or slow connections, you can ensure that they have a consistent and pleasant experience while interacting with your applications.