Mutations-want to solve using if-else condition

JavaScript
1

Tell us what’s happening:
For solving this problem can I use if else condition and satisfy all the cases? Please tell me I need help.

Your code so far

function mutation(arr) {
  var newArray=[];
   for(var i=0;i<arr.length;i++)
     {
       newArray.push(arr[i].toLowerCase());
     }
  
  
      if(newArray[0].indexOf(newArray[1]))
      {
        return true;
      }


    else if(newArray[0]!==newArray[1])
      {
        return false;
      }

  
}

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

Your browser information:

Your Browser User Agent is: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36.

Link to the challenge: