AnagramChecker

//(function() {
    let hashMap = {};
    let isAnagram = (str1, str2) => {

        if (str1.length !== str2.length) {
            return false;
        }

        // Create a hash mao of str2 character and increase value one (+1)
        createStr1HashMap(str1);

        let valueExist = createStr2HashMap(str2);

        return isStringsAnagram(valueExist);
    }

    let createStr1HashMap = (str1) => {
        [].map.call(str1, function (value, index, array) {
            hashMap[value] = value in hashMap ? (hashMap[value] + 1) : 1;
            return value;
        });
    }

    let createStr2HashMap = (str2) => {
        valueExist = [].every.call(str2, function (value, index, array) {
            if (value in hashMap) {
                hashMap[value] = hashMap[value] - 1;
            }
            return value in hashMap;
        });
        return valueExist;
    }

    function isStringsAnagram(valueExist) {
        if (!valueExist) {
            return valueExist;
        } else {
            let isAnagram;
            for (let i in hashMap) {
                if (hashMap[i] !== 0) {
                    isAnagram = false;
                    break;
                } else {
                    isAnagram = true;
                }
            }
            return isAnagram;
        }
    }



console.log(isAnagram('stackoverflow', 'flowerovstack')); // true
console.log(isAnagram('stackoverflow', 'flowervvstack')); // false

//})();