refactor(Hash Table): optimize character frequency sorting implementation

work/Baton-1/Medium/Hash Table/451.sort-characters-by-frequency.js

@@ -45,12 +45,18 @@
  * 	• 1 <= s.length <= 5 * 10^5
  *
  * 	• s consists of uppercase and lowercase English letters and digits.
-*/
+ */
 
 /**
  * @param {string} s
  * @return {string}
  */
-var frequencySort = function(s) {
+var frequencySort = function (s) {
+  const freq = {};
+  for (let c of s) freq[c] = (freq[c] || 0) + 1;
 
+  return s
+    .split("")
+    .sort((a, b) => freq[b] - freq[a] || a.localeCompare(b))
+    .join("");
 };