Understanding props in React: Why Passing as ({props}) Works

Описание: Learn why you can't retrieve state values in React using (props) and how destructuring with ({props}) solves the issue.
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This video is based on the question https://stackoverflow.com/q/69816367/ asked by the user 'Jonathan' ( https://stackoverflow.com/u/13282902/ ) and on the answer https://stackoverflow.com/a/69816472/ provided by the user 'Ernesto' ( https://stackoverflow.com/u/7366526/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding props in React: Why Passing as ({props}) Works

When working with React components, you might find yourself confused about how to pass and retrieve props effectively. One common question among React developers is: Why can I not retrieve the state value when passing as (props) but can when passing as ({props})? In this guide, we will dive deep into this issue with the help of a code example.

The Problem: Passing Props Incorrectly

Consider the following code snippet where we define a simple feedback application using React:

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

Here, we used <Statistics props={clicks} /> to pass the state variable clicks to the Statistics component. But why can’t we access the individual properties like props.good, props.neutral, etc.?

The Key Mistake

When you pass the clicks object as props={clicks}, the Statistics component receives it as:

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

As a result, you don’t get direct access to good, neutral, or bad. Instead, those values are nested within the props object. Therefore, when you try to access props.good, it doesn't exist, leading to errors.

The Solution: Destructuring Props

To fix this issue, you should use destructuring to pass the properties correctly. Instead of wrapping clicks in another object, you can use the spread operator to pass each property separately like so:

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

This way, the Statistics component will receive the props as:

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

Here’s How It Works

Destructuring with Spread Operator: By using {...clicks}, you are effectively spreading the clicks object properties and passing them as individual props.

Accessing Individual Props: Inside the Statistics component, you can now access props.good, props.neutral, and props.bad directly, giving you full access to their values. Your Statistics component can now work as intended:

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

Simplifying Code: Utilizing the spread operator not only resolves the issue but also keeps your code cleaner and more intuitive.

Conclusion

Getting props right in React is crucial for the smooth functioning of your application. The distinction between passing as (props) and destructuring with ({props}) is essential for correctly accessing your component's state values. By understanding the mechanics behind props and utilizing the spread operator, you can avoid common pitfalls and make your React applications much more efficient.

Now, you're equipped with this knowledge, so go ahead and build some incredible applications! If you have any further questions, don’t hesitate to reach out.