jsavascript foreach how to add an index code example

Example 1: javascript foreach index

users.forEach((user, index)=>{
	console.log(index); // Prints the index at which the loop is currently at
});

Example 2: what foreach method returns in javascript

function double(arr) {
  return arr.forEach(num => num*2);
}

console.log(double([1,2,3,4])) //undefined