Return true if the string in the first element of the array contains all of the letters of the string in the second element of the array
function mutation(arr) {
var arr1 = arr[0].toLowerCase().split('');
var arr2 = arr[1].toLowerCase().split('');
var count = 0;
for (let i =0; i < arr2.length; i++) {
if(arr1.indexOf(arr2[i]) > -1 ) {
count++;
}
}
return count == arr2.length
}
mutation(["hello", "hey"]);