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Learn how to effectively track dimensions of an array of refs in React components using hooks. Follow our step-by-step guide for a smooth implementation!
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How to Track Dimensions of an Array of Refs in React Using Hooks

When working with React components, it’s not uncommon to need to manage multiple elements and track their properties, such as dimensions. If you are rendering a dynamic list of children, you might find yourself in a situation where you need to create an array of refs and subsequently track their dimensions. This can be a bit tricky, especially if you need to ensure that you maintain the same number of refs across renders. In this guide, we will explore a useful solution that defines a way to track the dimensions of an array of refs in your React application.

Understanding the Challenge

The main challenge arises from React's requirement that the number of refs called in a component must remain constant between renders. This is particularly problematic when dealing with a dynamic number of children, as the length may change during the lifecycle of the component. Traditional looping techniques for ref management, like calling a hook inside a loop, will not work because they violate React's rendering rules.

Key Considerations

Consistent Number of Refs: You must ensure that refs are defined consistently each time the component re-renders.

Dynamic Content: The children passed to the component may vary, requiring a flexible solution.

The Solution: Using a Child Wrapper

The proposed solution involves creating a wrapper component called ChildWrapper. This component will manage a ref and act as a bridge to communicate with the parent component, allowing it to track the dimensions of each child element.

Implementing the Child Wrapper

Define the Child Wrapper Component:

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

Using the Child Wrapper in the Main Component:
In your main component (let's call it Test), you will call the ChildWrapper for each child:

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

Explanation of the Code

ChildWrapper Component: This component takes children and a setRect function as props. It initializes a ref and uses the useBoundingRect hook to track its dimensions. Every time the dimensions update, it calls setRect to notify the parent component.

Test Component: It maintains an array of dimensions using the rects state. It defines a helper function setRect that updates the specific rectangle by index. The ChildWrapper is rendered inside a map function, allowing you to dynamically pass each child element along with its corresponding setRect function.

Conclusion

By utilizing a ChildWrapper component, you can effectively track the dimensions of an array of refs without violating React's rules. This approach allows for clear separation of concerns, facilitates communication of dimensions between child and parent components, and maintains the functionality you need in dynamic situations.

Now that you know how to manage refs and track dimensions in your React components, you can apply this knowledge to enhance the interactivity and responsiveness of your applications.

The solution discussed here empowers developers to harness the full potential of React hooks while working with dynamic component structures. Whether building complex forms or interactive lists, managing refs this way provides both stability and scalability.

Try It Out

Give this solution a try in your next React project and simplify your state management around dimensions of multiple elements. Happy coding!