Understanding Why requestAnimationFrame Doesn't Repeatedly Update Your React Component

In this guide, we will explore the common issue of `requestAnimationFrame` not updating a React component repeatedly and provide effective solutions to ensure real-time updates in your UI.
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This video is based on the question stackoverflow.com/q/71397341/ asked by the user 'MythLoud' ( stackoverflow.com/u/17337257/ ) and on the answer stackoverflow.com/a/71397893/ provided by the user 'Will Jenkins' ( stackoverflow.com/u/93812/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Why Your requestAnimationFrame Isn’t Updating Your React Component

If you're working with React and trying to create animations or updates in your UI that involve requestAnimationFrame, you might run into an issue where your component doesn’t seem to update as expected. In this post, we will break down the problem and explain how to effectively resolve it.

The Problem: What’s Happening?

You may have encountered a scenario where you have written code using requestAnimationFrame, yet your React component only displays the initial value of a variable. For example, you might have a count variable that increments with each frame but does not render the updated value in your component. Here’s a simplified version of what you might see:

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

In this example, you might find that the count value only updates the very first time, and subsequent updates do not appear in your UI.

The Root Cause

The reason your count value is not updating in the DOM is that React needs a way to track changes to the component’s state or props. In its current form, the UpdateComponents function isn’t linked to any state management. Thus, React is unaware that it needs to re-render the component after the value of count changes.

Key Points

React Needs State: React components will not automatically re-render unless they are tied to state or props change.

requestAnimationFrame Is Still Working: You can confirm that requestAnimationFrame is functioning correctly by logging count to the console. You will see it update, but the UI will not reflect these changes.

The Solution: Using State to Track Updates

To solve this problem, you should utilize React’s state management via the useState hook. This ensures that any changes to count will trigger a re-render of your component.

Implementing the Solution

Here’s how to modify your code accordingly:

Import useState: Bring in useState from React.

Initialize State: Replace the plain variable count with a state variable.

Update State: Use the state updater function to increment the count.

Here is an updated version of your code:

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

Explanation of Changes:

Using useState: The count variable is now managed by state, ensuring that any updates rerender the component.

Using useEffect: The updateComponents function is called in an effect, which starts the animation on component mount.

setCount Function: The updater function from useState increments the count, which notifies React to rerender the component.

Final Thoughts

By transitioning from mutable variables to a state management approach with React, you can ensure that your components update in real-time in response to variable changes. This not only enhances the performance of your UI but also aligns with React’s design principles for managing component behavior and lifecycle.

In conclusion, remember to always connect your updates to state changes, especially when working with animations and dynamic updates in React!