mutations.js

// 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) {
  // console.log(arr[1].toLowerCase().split(''))
  return arr[1].toLowerCase()
               .split('')
               .every((letter) => {
                  // console.log(arr[0].toLowerCase().indexOf(letter));
                  return arr[0].toLowerCase()
                    .indexOf(letter) != -1;
                  });
}

console.log(mutation(["hello", "hey"]));
console.log(mutation(["hello", "neo"]));
console.log(mutation(["zyxwvutsrqponmlkjihgfedcba", "qrstu"]));