[12.x] Feature: Collection chunk without preserving keys (#54916)

* add test

* implement chunking without preserving keys for support collection

* implement chunking without preserving keys for lazy collection

src/Illuminate/Collections/Collection.php

@@ -1441,17 +1441,18 @@ public function firstOrFail($key = null, $operator = null, $value = null)
      * Chunk the collection into chunks of the given size.
      *
      * @param  int  $size
+     * @param  bool  $preserveKeys
      * @return static<int, static>
      */
-    public function chunk($size)
+    public function chunk($size, $preserveKeys = true)
     {
         if ($size <= 0) {
             return new static;
         }
 
         $chunks = [];
 
-        foreach (array_chunk($this->items, $size, true) as $chunk) {
+        foreach (array_chunk($this->items, $size, $preserveKeys) as $chunk) {
             $chunks[] = new static($chunk);
         }
 

src/Illuminate/Collections/LazyCollection.php

@@ -1376,22 +1376,28 @@ public function firstOrFail($key = null, $operator = null, $value = null)
      * Chunk the collection into chunks of the given size.
      *
      * @param  int  $size
+     * @param  bool  $preserveKeys
      * @return static<int, static>
      */
-    public function chunk($size)
+    public function chunk($size, $preserveKeys = true)
     {
         if ($size <= 0) {
             return static::empty();
         }
 
-        return new static(function () use ($size) {
+        $add = match ($preserveKeys) {
+            true => fn (array &$chunk, Traversable $iterator) => $chunk[$iterator->key()] = $iterator->current(),
+            false => fn (array &$chunk, Traversable $iterator) => $chunk[] = $iterator->current(),
+        };
+
+        return new static(function () use ($size, $add) {
             $iterator = $this->getIterator();
 
             while ($iterator->valid()) {
                 $chunk = [];
 
                 while (true) {
-                    $chunk[$iterator->key()] = $iterator->current();
+                    $add($chunk, $iterator);
 
                     if (count($chunk) < $size) {
                         $iterator->next();

tests/Support/SupportCollectionTest.php

@@ -2145,6 +2145,24 @@ public function testChunkWhenGivenLessThanZero($collection)
         );
     }
 
+    #[DataProvider('collectionClassProvider')]
+    public function testChunkPreservingKeys($collection)
+    {
+        $data = new $collection([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
+
+        $this->assertEquals(
+            [[0 => 1, 1 => 2, 2 => 3], [3 => 4, 4 => 5, 5 => 6], [6 => 7, 7 => 8, 8 => 9], [9 => 10]],
+            $data->chunk(3)->toArray()
+        );
+
+        $data = new $collection([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
+
+        $this->assertEquals(
+            [[1, 2, 3], [4, 5, 6], [7, 8, 9], [10]],
+            $data->chunk(3, false)->toArray()
+        );
+    }
+
     #[DataProvider('collectionClassProvider')]
     public function testSplitIn($collection)
     {