where to return a value in a foreach javascript code example

Example 1: foreach loop javascript

const numList = [1, 2, 3];

numList.forEach((number) => {
  console.log(number);
});

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