I felt so happy when I solved this challenge, then came here and saw how elegantly many of you fellow campers solved it. It’s fun how many ways there are to solve a problem. Here’s my, rather verbose, solution. Any suggestions for improvement much appreciated 
function mutation(arr) {
// create arrays to house characters of strings we want to compare
var arr1 = ;
var arr2 = ;// create array for characters that are present in both strings
var arr1_1 = ;// split strings to compare into arrays
arr1 = arr[0].toLowerCase().split(“”);
arr2 = arr[1].toLowerCase().split(“”);for (var i = 0; i < arr2.length; i++) {
// check if arr1 includes each character from arr2 if (arr1.includes(arr2[i])) { // if arr2(i) is found in arr1 push it to a new array arr1_1.push(arr2[i]); }}
// join arr1_1 into a string
var strToCompare = arr1_1.join([separator = “”]);// compare the new string to arr[1]
if (arr[1].toLowerCase() == strToCompare) {
return true;
}
return false;}