Sort Characters By Frequency— refactored

sortCharFreq.js

//Given a string, sort it in decreasing order based on the frequency of characters.

var test = "Aabb";

var frequencySort = function(s) {
  var counter = {};
  var sortedArr = [];
  var theStr = "";
  
  for(var i = 0; i < s.length; i++){
    if(!counter.hasOwnProperty(s.charAt(i))){
      counter[s.charAt(i)] = 1;
    }
    else{
      counter[s.charAt(i)] += 1;
    }
  }
  
  for(var char in counter){
    sortedArr.push([char, counter[char]]);
  }
  sortedArr.sort(function(a, b){
    return b[1] - a[1];
  });
  
  sortedArr.forEach(function(el){
    while(el[1] > 0){
      theStr += el[0];
      el[1]--;
    }
  });
  return theStr;
};

console.log(frequencySort(test));