What do these symbols do in React?

Question

React

React code questions:

<button className={`tablinks ${i === active ? 'active' : ''}`}
            onClick={openTab}
            data-index={i}
>{n.title}</button>

1) I often see the $ symbol in React code, what does it do in specific code? and in general in React what is it used for?
2) Symbol ? Is this an alternative to the if condition? whereas the code I wrote would look like with if? I just want to understand such a react construction but c if to make it more clear.

Answer 1

1. https://developer.mozilla.org/ru/docs/Web/JavaScri...
2. https://developer.mozilla.org/ru/docs/Web/JavaScri...
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