patch

src/Mapper.php

@@ -56,7 +56,7 @@ public static function from(array|object $data): static
                 }
             }
 
-            if (is_array($value) && is_subclass_of($param->getType()->getName(), self::class)) {
+            if (is_array($value) && ! $param->getType() instanceof \ReflectionUnionType && is_subclass_of($param->getType()->getName(), self::class)) {
                 $class = $param->getType()->getName();
                 $value = $class::from($value);
             }

tests/MapperTest.php

@@ -12,6 +12,7 @@
 use AnourValar\LaravelAtom\Tests\Mappers\ArrayOfMapper;
 use AnourValar\LaravelAtom\Tests\Mappers\ExcludeMapper;
 use AnourValar\LaravelAtom\Tests\Models\Post;
+use AnourValar\LaravelAtom\Tests\Mappers\OptionalMapper;
 
 class MapperTest extends \Orchestra\Testbench\TestCase
 {
@@ -187,6 +188,36 @@ public function test_arrayOf_exclude()
         );
     }
 
+    /**
+     * @return void
+     */
+    public function test_optional()
+    {
+        // Empty
+        $this->assertSame([], OptionalMapper::from([])->toArray());
+
+        // A
+        $this->assertSame(['a' => ['foo']], OptionalMapper::from(['a' => ['foo']])->toArray());
+
+        // B
+        $this->assertSame(
+            ['b' => [['a' => '1', 'b' => 2, 'c' => null, 'd' => 1]]],
+            OptionalMapper::from(['b' => [['a' => 1, 'b' => 2]]])->toArray()
+        );
+
+        // A + B
+        $this->assertSame(
+            [
+                'a' => ['foo'],
+                'b' => [['a' => '1', 'b' => 2, 'c' => null, 'd' => 1], ['a' => '3', 'b' => 4, 'c' => '5', 'd' => 6], ['a' => '7', 'b' => 8, 'c' => null, 'd' => 1]],
+            ],
+            OptionalMapper::from([
+                'a' => ['foo'],
+                'b' => [['a' => 1, 'b' => 2], SimpleMapper::from(['a' => 3, 'b' => 4, 'c' => 5, 'd' => 6]), new SimpleMapper(7, 8)],
+            ])->toArray()
+        );
+    }
+
     /**
      * @return void
      */

tests/Mappers/OptionalMapper.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace AnourValar\LaravelAtom\Tests\Mappers;
+
+use AnourValar\LaravelAtom\Mapper;
+use AnourValar\LaravelAtom\Mapper\ArrayOf;
+use AnourValar\LaravelAtom\Mapper\Mapping;
+use AnourValar\LaravelAtom\Mapper\MappingSnakeCase;
+use AnourValar\LaravelAtom\Mapper\Optional;
+
+class OptionalMapper extends Mapper
+{
+    public function __construct(
+        public array|Optional $a,
+        #[ArrayOf(SimpleMapper::class)]
+        public array|Optional $b,
+    ) {
+
+    }
+}