Add collapseWithKeys to Collection

src/Illuminate/Collections/Collection.php

@@ -141,6 +141,28 @@ public function collapse()
         return new static(Arr::collapse($this->items));
     }
 
+    /**
+     * Collapse the collection of items into a single array while preserving its keys.
+     *
+     * @return static<mixed, mixed>
+     */
+    public function collapseWithKeys()
+    {
+        $results = [];
+
+        foreach ($this->items as $key => $values) {
+            if ($values instanceof Collection) {
+                $values = $values->all();
+            } elseif (! is_array($values)) {
+                continue;
+            }
+
+            $results[$key] = $values;
+        }
+
+        return new static(array_replace(...$results));
+    }
+
     /**
      * Determine if an item exists in the collection.
      *

src/Illuminate/Collections/LazyCollection.php

@@ -194,6 +194,24 @@ public function collapse()
         });
     }
 
+    /**
+     * Collapse the collection of items into a single array while preserving its keys.
+     *
+     * @return static<mixed, mixed>
+     */
+    public function collapseWithKeys()
+    {
+        return new static(function () {
+            foreach ($this as $values) {
+                if (is_array($values) || $values instanceof Enumerable) {
+                    foreach ($values as $key => $value) {
+                        yield $key => $value;
+                    }
+                }
+            }
+        });
+    }
+
     /**
      * Determine if an item exists in the enumerable.
      *

tests/Support/SupportCollectionTest.php

@@ -1722,6 +1722,20 @@ public function testCollapseWithNestedCollections($collection)
         $this->assertEquals([1, 2, 3, 4, 5, 6], $data->collapse()->all());
     }
 
+    #[DataProvider('collectionClassProvider')]
+    public function testCollapseWithKeys($collection)
+    {
+        $data = new $collection([[1 => 'a'], [3 => 'c'], [2 => 'b'], 'drop']);
+        $this->assertEquals([1 => 'a', 3 => 'c', 2 => 'b'], $data->collapseWithKeys()->all());
+    }
+
+    #[DataProvider('collectionClassProvider')]
+    public function testCollapseWithKeysOnNestedCollections($collection)
+    {
+        $data = new $collection([new $collection(['a' => '1a', 'b' => '1b']), new $collection(['b' => '2b', 'c' => '2c']), 'drop']);
+        $this->assertEquals(['a' => '1a', 'b' => '2b', 'c' => '2c'], $data->collapseWithKeys()->all());
+    }
+
     #[DataProvider('collectionClassProvider')]
     public function testJoin($collection)
     {