How to change styles on a specific React child element?

Question

JavaScript

How to change the styles of a specific child element that was clicked on on click?
Here is my code:

<div>
{arr.map((res, key) => (
<span key={key} onClick('что здесь писать?') className={'elem'}>{res + 1} элемент</span>
))}
</div>

Answer 1

If the logic for receiving data is very similar, and only, for example, addresses for the API change, then you can do everything in one place. If the differences are large enough, then it is better to split it so that it is easier to maintain later.

Answer 2

handleClick=(e)=>{
e.preventDefault();
e.target.style.color = 'black'
console.log(e.target);
}