Javascript String mutation(arr)

/*//from   ww w .j  ava 2s  . co  m

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.

For example, ["hello", "Hello"], should return true because all of the letters in the second string are present in the first, ignoring case.

The arguments ["hello", "hey"] should return false because the string "hello" does not contain a "y".

Lastly, ["Alien", "line"], should return true because all of the letters in "line" are present in "Alien".

Remember to use Read-Search-Ask if you get stuck. Write your own code.

Here are some helpful links:

String.prototype.indexOf()

*/

function mutation(arr) {
  return arr[1].toLowerCase().split('').every(function(value) {
      return arr[0].toLowerCase().split('').indexOf(value) !== -1;
  });
}

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