Find max occurence of chars in a string

findMaxOccurence.js

function findMaxOccurence(str) {
	var map = new Map();
	var max = 0;

	for (var i = 0; i < str.length; i++) {

		if (map.has(str.charAt(i))) {
			map.set(str.charAt(i), map.get(str.charAt(i)) + 1);
		} else {
			map.set(str.charAt(i), 1);
		}
		max = max < map.get(str.charAt(i)) ? map.get(str.charAt(i)) : max;
	}

	var result = [];
	for (var i = 0; i <= map.size; i++) {

		if (map.get(str.charAt(i)) === max && result.indexOf(str.charAt(i)) < 0) {
			result.push(str.charAt(i));
		}
	}


	/*var result = [];
	 var arrKey = Array.from(map.keys());
	 for (var i = 0; i < arrKey.length; i++) {
	 if (map.get(arrKey[i]) == max) result.push(arrKey[i]);
	 }
	 }*/

	return result;

}


function findMaxOccurenceUsingObject(str) {
	var arr = str.split('');

	var map = {};
	var max = 0;

	for (var i in arr) {
		map[arr[i]] = map[arr[i]] === undefined ? 1 : map[arr[i]] + 1;
		max = map[arr[i]] > max ? map[arr[i]] : max;
	}

	var output = [];
	for (var i in map) {
		if (map[i] === max) output.push(i);
	}

	return output;

}

console.log(findMaxOccurence('helloaa'));
console.log(findMaxOccurenceUsingObject('helloaa'));