Скачать или смотреть Optimize Your JavaScript Application: Update the View Only on Value Changes

Learn how to enhance your JavaScript application by updating the chart only when data changes instead of at regular intervals. Improve performance and user experience with this step-by-step guide!
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This video is based on the question https://stackoverflow.com/q/66258506/ asked by the user 'mar24n' ( https://stackoverflow.com/u/12390596/ ) and on the answer https://stackoverflow.com/a/66258692/ provided by the user 'sourav satyam' ( https://stackoverflow.com/u/11834630/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Optimize Your JavaScript Application: Update the View Only on Value Changes

When working with real-time data, like values from a WebSocket server, an essential challenge that many developers face is how to efficiently update the view (like a chart) when the data changes. In this article, we will explore a common scenario with JavaScript where the view updates every second, even when the data hasn't changed. We will then show you how to optimize your JavaScript code to update the view only when there is a change in the value.

The Problem

You have a JavaScript chart that retrieves data from a WebSocket server every second. Currently, your view (the chart) gets updated regardless of whether the data value has changed or not. This approach not only consumes unnecessary processing resources but also leads to an inefficient user experience. Your goal is to make updates only when a new, different value is available.

The Solution

To solve the problem of updating the view solely on value changes, we can implement a simple mechanism that checks if the new data is different from the last received value. Here’s a step-by-step guide on how to achieve this using JavaScript.

Step 1: Store the Previous Value

We will introduce an object to store the state of the last known values. This will help us compare new incoming values with the previous ones. Here's a basic initialization:

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

Step 2: Modify the Data Fetching Logic

Instead of updating the chart every second, you will modify your existing AJAX call to include a check that only updates the chart when the value is different. Here’s the revised implementation that uses the stored values to determine whether to update the chart or not.

Code Example

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

Explanation of the Code

setInterval: We set up an interval that runs every second to check for updates from the server.

XMLHttpRequest: This is used to make API calls to retrieve the latest value.

Value Checking Logic: Before updating the chart, we check if the received value y already exists in the change object. If it doesn't, we update the chart.

Efficiency: By only updating the view if the value has truly changed, we reduce unnecessary computations, improve performance, and enhance the overall user experience.

Conclusion

By implementing these changes, you can optimize your JavaScript application to update the chart only when the value changes. This not only streamlines performance but also provides a cleaner and more responsive user interface. Now you can enjoy an efficient and effective way to handle real-time data updates without overwhelming your application with unnecessary refreshes!

With these strategies, you’ll be able to create a more efficient application that benefits both you and your users. Happy coding!