Se agrega método Arr::nested() como el contrario de Arr:dot() y sus tests.

Author: estebandelaf

src/Arr.php

@@ -47,6 +47,37 @@ public static function dot(array $array, string $prefix = ''): array
         return $result;
     }
 
+    /**
+     * Converts a flat array with dot notation keys back to a multi-dimensional
+     * array.
+     *
+     * @param array $array The flat array with dot notation keys.
+     * @return array The multi-dimensional array.
+     */
+    public static function nested(array $array): array
+    {
+        $result = [];
+        foreach ($array as $key => $value) {
+            if (str_contains($key, '.')) {
+                $keys = explode('.', $key);
+                $current = &$result;
+
+                foreach ($keys as $k) {
+                    if (!isset($current[$k]) || !is_array($current[$k])) {
+                        $current[$k] = [];
+                    }
+                    $current = &$current[$k];
+                }
+
+                $current = $value;
+            } else {
+                $result[$key] = $value;
+            }
+        }
+
+        return $result;
+    }
+
     /**
      * Recursively casts array values automatically based on their content.
      *

tests/src/Arr/ArrDotNestedTest.php

@@ -0,0 +1,113 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Derafu: Support - Essential PHP Utilities.
+ *
+ * Copyright (c) 2025 Esteban De La Fuente Rubio / Derafu <https://www.derafu.dev>
+ * Licensed under the MIT License.
+ * See LICENSE file for more details.
+ */
+
+namespace Derafu\TestsSupport\Arr;
+
+use Derafu\Support\Arr;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+#[CoversClass(Arr::class)]
+class ArrDotNestedTest extends TestCase
+{
+    #[Test]
+    #[DataProvider('provideDotData')]
+    public function shouldFlattenArrayWithDotNotation(
+        array $input,
+        string $prefix,
+        array $expected
+    ): void {
+        $result = Arr::dot($input, $prefix);
+        $this->assertSame($expected, $result);
+    }
+
+    public static function provideDotData(): array
+    {
+        return [
+            'simple nested array' => [
+                ['a' => ['b' => 'c']],
+                '',
+                ['a.b' => 'c'],
+            ],
+            'with prefix' => [
+                ['a' => ['b' => 'c']],
+                'x',
+                ['x.a.b' => 'c'],
+            ],
+            'flat array' => [
+                ['a' => 1, 'b' => 2],
+                '',
+                ['a' => 1, 'b' => 2],
+            ],
+            'empty array' => [
+                [],
+                '',
+                [],
+            ],
+        ];
+    }
+
+    #[Test]
+    #[DataProvider('provideNestedData')]
+    public function shouldConvertDotNotationToNestedArray(
+        array $input,
+        array $expected
+    ): void {
+        $result = Arr::nested($input);
+        $this->assertSame($expected, $result);
+    }
+
+    public static function provideNestedData(): array
+    {
+        return [
+            'simple dot notation' => [
+                ['a.b' => 'c'],
+                ['a' => ['b' => 'c']],
+            ],
+            'flat array' => [
+                ['a' => 1, 'b' => 2],
+                ['a' => 1, 'b' => 2],
+            ],
+            'empty array' => [
+                [],
+                [],
+            ],
+        ];
+    }
+
+    #[Test]
+    #[DataProvider('provideCycleData')]
+    public function shouldCompleteCycleDotToNestedAndBack(
+        array $original
+    ): void {
+        $dot = Arr::dot($original);
+        $nested = Arr::nested($dot);
+        $this->assertSame($original, $nested);
+    }
+
+    public static function provideCycleData(): array
+    {
+        return [
+            'simple nested structure' => [
+                ['a' => ['b' => 'c']],
+            ],
+            'flat array' => [
+                ['a' => 1, 'b' => 2],
+            ],
+            'empty array' => [
+                [],
+            ],
+        ];
+    }
+}