Logic for Mutations problem

JavaScript
1

Tell us what’s happening:
Basically, my logic for solving this problem is following:

  1. check each letters of second array exist in the first array
  2. give true if there are same letters
  3. give true if every values of answer is true, if not, give false

but, in some case, It makes problems.
any advice and critics will be appreciated.

Your code so far

function mutation(arr) {
  var firstArr=arr[0].toLowerCase().split("");
  var secondArr=arr[1].toLowerCase().split("");
  var result=[];
  var answer=[];
    
  for(i=0;i<firstArr.length;i++) {
    for(n=0;n<secondArr.length;n++) {
      result[i]=secondArr[n]==firstArr[i]? true:false;
      answer[n]=result.indexOf(true)!==-1? true:false;
    }
  }
  
  return answer.indexOf(false)!==-1? false:true;
}

mutation(["Mary", "Aarmy"]);

Your browser information:

Your Browser User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36.

Link to the challenge:
https://www.freecodecamp.org/challenges/mutations