Add input validation for empty or invalid array in binary search

Search/BinarySearch.js

@@ -8,44 +8,46 @@
  */
 
 function binarySearchRecursive(arr, x, low = 0, high = arr.length - 1) {
+  if (!Array.isArray(arr) || arr.length === 0) {
+    return -1
+  }
+
   const mid = Math.floor(low + (high - low) / 2)
 
   if (high >= low) {
     if (arr[mid] === x) {
-      // item found => return its index
       return mid
     }
 
     if (x < arr[mid]) {
-      // arr[mid] is an upper bound for x, so if x is in arr => low <= x < mid
       return binarySearchRecursive(arr, x, low, mid - 1)
     } else {
-      // arr[mid] is a lower bound for x, so if x is in arr => mid < x <= high
       return binarySearchRecursive(arr, x, mid + 1, high)
     }
-  } else {
-    // if low > high => we have searched the whole array without finding the item
-    return -1
   }
+
+  return -1
 }
+
 function binarySearchIterative(arr, x, low = 0, high = arr.length - 1) {
+  if (!Array.isArray(arr) || arr.length === 0) {
+    return -1
+  }
+
   while (high >= low) {
     const mid = Math.floor(low + (high - low) / 2)
 
     if (arr[mid] === x) {
-      // item found => return its index
       return mid
     }
 
     if (x < arr[mid]) {
-      // arr[mid] is an upper bound for x, so if x is in arr => low <= x < mid
       high = mid - 1
     } else {
-      // arr[mid] is a lower bound for x, so if x is in arr => mid < x <= high
       low = mid + 1
     }
   }
-  // if low > high => we have searched the whole array without finding the item
+
   return -1
 }