React

HTML

<div id="app"></div>

React

const App = () => {

	const someArray = [2, 3, 1, 4, 5, 3]; 

	return (
  	<div>
  	  <h2>Example</h2>
      <h3>Not using third argument</h3>
      {someArray.map(item => {
      	return someArray[item];
      })}
      <h3>Using third argument</h3>
      {someArray.map((item, ind, arr) => {
      	return arr[item];
      })}
  	</div>
  );
}

ReactDOM.render(<App />, document.querySelector("#app"))