When keys are given to lists in render function, those keys should be? code example

Example 1: map function in react

function NameList() {
	const names = ['Bruce', 'Clark', 'Diana']
    return (
    	<div>
      {names.map(name => <h2>{name}</h2>)}
      	</div>
    )
}

Example 2: react create list of array in react

const App = props => {  const quoteArray = props.quotes.map((quote) => {    return (      <Quote text={quote.text} author={quote.author} />    );  });  return (    <div>      <h2>Famous Quotes</h2>      {quoteArray}    </div>  );};App.propTypes = {  quotes: React.PropTypes.array}