Avoid mutating input array in bubble sort implementations

Author: MayankSharma-2812

Sorts/BubbleSort.js

@@ -1,33 +1,30 @@
 /* Bubble Sort is an algorithm to sort an array. It
- *  compares adjacent element and swaps their position
- *  The big O on bubble sort in worst and best case is O(N^2).
- *  Not efficient.
- *  Somehow if the array is sorted or nearly sorted then we can optimize bubble sort by adding a flag.
+ * compares adjacent elements and swaps their position.
+ * The big O on bubble sort in worst and best case is O(N^2).
  *
- *  In bubble sort, we keep iterating while something was swapped in
- *  the previous inner-loop iteration. By swapped I mean, in the
- *  inner loop iteration, we check each number if the number proceeding
- *  it is greater than itself, if so we swap them.
- *
- *  Wikipedia: https://en.wikipedia.org/wiki/Bubble_sort
- *  Animated Visual: https://www.toptal.com/developers/sorting-algorithms/bubble-sort
+ * Wikipedia: https://en.wikipedia.org/wiki/Bubble_sort
  */
 
 /**
  * Using 2 for loops.
  */
-export function bubbleSort(items) {
+export function bubbleSort(list) {
+  if (!Array.isArray(list)) {
+    throw new TypeError('Given input is not an array')
+  }
+
+  if (list.length === 0) {
+    return []
+  }
+
+  const items = [...list]
   const length = items.length
   let noSwaps
 
   for (let i = length; i > 0; i--) {
-    // flag for optimization
     noSwaps = true
-    // Number of passes
     for (let j = 0; j < i - 1; j++) {
-      // Compare the adjacent positions
       if (items[j] > items[j + 1]) {
-        // Swap the numbers
         ;[items[j], items[j + 1]] = [items[j + 1], items[j]]
         noSwaps = false
       }
@@ -43,7 +40,16 @@ export function bubbleSort(items) {
 /**
  * Using a while loop and a for loop.
  */
-export function alternativeBubbleSort(arr) {
+export function alternativeBubbleSort(list) {
+  if (!Array.isArray(list)) {
+    throw new TypeError('Given input is not an array')
+  }
+
+  if (list.length === 0) {
+    return []
+  }
+
+  const arr = [...list]
   let swapped = true
 
   while (swapped) {