The map() method creates a new array populated with the results of calling a provided function on every element in the calling array.

const array1 = [1,4,9,16];
// pass a function to map
const map1 = array1.map(x => x * 2);

console.log(map1);
// expected output: Array [2, 8, 18, 32]

let numbers = [1, 4, 9]
let roots = numbers.map(function(num) {
  return Math.sqrt(num)
})

console.log(roots);