Скачать или смотреть How to Fix the Interaction Issue in Your React Calculator App

Discover why the value isn't being passed to the other component in your React app and learn how to fix it seamlessly!
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This video is based on the question https://stackoverflow.com/q/72219193/ asked by the user 'ubsd' ( https://stackoverflow.com/u/18236192/ ) and on the answer https://stackoverflow.com/a/72219311/ provided by the user 'Wasim Abuzaher' ( https://stackoverflow.com/u/6010005/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the Challenge: Passing Values Between Components in React

If you're diving into the world of React and trying to build interactive components, you might run into a common issue: values not being passed correctly between components. In this post, we will explore a simple scenario involving a calculator where the button clicked should display its value on the screen. Let's unpack the problem and the solution step-by-step.

The Problem

You've set up a React app that is intended to become a calculator. However, you may have noticed that when you click on a button, the desired value doesn't appear in the display area. Below is the code that represents your current setup:

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

What's Wrong?

The problem is that the Button component does not actually call the function that updates the parent state when a button is clicked. Instead, it tries to assign the button value to a non-existent property str on this.props, and does nothing with it. Therefore, the display doesn't get updated with the button's value.

The Solution: Correctly Passing Data to Parent Components

To allow the buttons to communicate effectively with the parent component (App), you need to make a couple of changes. Here’s how to do it:

Step 1: Update the Button Component

Instead of trying to set a property on this.props, you should call a function that is passed from the parent. Here's how to modify your Button component:

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

Step 2: Pass the Event Handler to Each Button

When you render each Button, pass the handleCallback as a prop. This ensures that when a button is clicked, the parent component is notified, and the state is updated appropriately:

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

Conclusion

With these modifications, each button will properly communicate with the parent App component, and the display will update seamlessly whenever a button is clicked. This simple fix highlights one of the core concepts in React — how to efficiently pass data and callbacks between components.

Now you can move forward with adding more features to your calculator! Happy coding!