Adding 344-Reverse-String.js

Author: FahadulShadhin

javascript/344-Reverse-String.js

@@ -0,0 +1,16 @@
+/**
+ * @param {character[]} s
+ * @return {void} Do not return anything, modify s in-place instead.
+ */
+ var reverseString = function(s) {
+    let i = 0, j = s.length-1;
+    
+    while(i <= j) {
+        let leftval = s[i], rightval = s[j];
+        s[i] = rightval;
+        s[j] = leftval;
+        
+        i++;
+        j--;
+    }
+};