.forEach .map() loop JavaScript

For Each .forEach iterates the elements of an array but does not return a value.

const a = [1, 2, 3];
const newArray = a.forEach((num, index) => {
  //do something 
});

// newArray = undefined

Map .map iterates the elements of an array but return a new array.

const a = [1, 2, 3];
const newArray = a.map(num => {
  return num * 2;
});

// newArray = [2, 4, 6]