aded comment

Author: mauricechouam

Missing Number/code.js

@@ -1,11 +1,12 @@
 var missingNumber = function (nums) {
-    let xor = 0; 
+    let xor = 0;
     for (let i = 0; i < nums.length; i++) {
         if (nums[i] != 0)// remove thyis condition keeping the body if no zero slot
             xor ^= nums[i];
         xor ^= (i + 1);
 
     }
     return xor;
-    
-}
+    //return XOR ^ ARRAY.length + 1; if your array doesn't have empty zero slot. 
+
+};