default key for maps react 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: jsx map with index

materials.map((material,index) => console.log(index +" = " + material + " = " + materials[index]));