Oletem
1/10/2018 - 1:06 PM

Mutations

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".

.js
content_copyfile_download

function mutation(arr) {
  var target = arr[0].toLowerCase();//we are selecting first wor in array[hello]
  var test = arr[1].toLowerCase();//and second[hey] making them both lowercase, indexOf is case sensitive
  
  for(var i =0; i<test.length;i++){//creating a loop at a length of test string
    
    if(target.indexOf(test[i])===-1)//-1 is equal to not finding a match 
    /*we are comparing whole target(hello) for match with each and every letter of test(hey)*/
      
      return false;
  }
  
  return true;
}

mutation(["hello", "hey"]);

Intermediate Code Solution:
Declarative

function mutation(arr) {
  return arr[1].toLowerCase()
    .split('')
    .every(function(letter) {
      return arr[0].toLowerCase()
        .indexOf(letter) !== -1;
    });
}
:rocket: Run Code71

Code Explanation:
Grab the second string, lowercase and turn it into an array; then make sure every one of its letters is a part of the lowercased first string.

Every will basically give you letter by letter to compare, which we do by using indexOf on the first string. indexOf will give you -1 if the current letter is missing. We check that not to be the case, for if this happens even once every will be false.