Slice and Splice: toString is necessary?

I don’t understand whether should I turn each array element into a character but stored it in an array, should I?
If so, I tried this with map, trying to map each element to toString. So, what am I doing wrong?

function frankenSplice(arr1, arr2, n) {
  let array2Copy = arr2.slice(0);
  for (let i = 0; i < arr1.length; i++){
    array2Copy.splice(n, 0, arr1[i]);
let result = => i.toString());   

  return result;

console.log(frankenSplice([1, 2, 3], [4, 5], 1));//-->4,3,2,1,5
frankenSplice([1, 2], ["a", "b"], 1);//-->a,2,1,b

well, you set your mapped toString stuff into result, then you never actually DO anything with result

Instead of creating a new array, you can always simply do

array2Copy =*your map function*/);

return array2Copy;

Yeah… with `result It is still the same issue.