feat: JsonForceEmptyObjectAsArray cast

README.md

@@ -1206,6 +1206,12 @@ To make those types usable, these casts can be used with your eloquent models:
 | `integerArray` | `Tpetry\PostgresqlEnhanced\Eloquent\Casts\IntegerArrayCast` |
 | `vector`       | `Tpetry\PostgresqlEnhanced\Eloquent\Casts\VectorArray`      |
 
+Additionally, these casts exist to make using PostgreSQL more easy:
+
+| Cast                                                                   | Description                                                                                            |
+|------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------|
+| `Tpetry\PostgresqlEnhanced\Eloquent\Casts\JsonForceEmptyObjectAsArray` | Decodes JSON value as array in Laravel but ensures that empty values are always stored as JSON object. |
+
 ### Refresh Data on Save
 
 When you are using Laravel's `storedAs($expression)` feature in migrations to have dynamically computed columns in your database or triggers to update these columns, eloquent's behaviour is not doing exactly what you are expecting.

src/Eloquent/Casts/JsonForceEmptyObjectAsArray.php

@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tpetry\PostgresqlEnhanced\Eloquent\Casts;
+
+use Illuminate\Contracts\Database\Eloquent\CastsAttributes;
+
+class JsonForceEmptyObjectAsArray implements CastsAttributes
+{
+    /**
+     * Transform the attribute from the underlying model values.
+     *
+     * @param \Illuminate\Database\Eloquent\Model $model
+     * @param ?string $value
+     *
+     * @return ?array<array-key, mixed>
+     */
+    public function get($model, string $key, mixed $value, array $attributes): ?array
+    {
+        if (null === $value) {
+            return null;
+        }
+
+        return json_decode($value, true, flags: \JSON_THROW_ON_ERROR);
+    }
+
+    /**
+     * Transform the attribute to its underlying model values.
+     *
+     * @param \Illuminate\Database\Eloquent\Model $model
+     * @param array<array-key, mixed>|\Illuminate\Support\Collection<array-key, mixed>|null $value
+     */
+    public function set($model, string $key, mixed $value, array $attributes): ?string
+    {
+        if (null === $value) {
+            return null;
+        }
+
+        return match ($casted = json_encode($value, flags: \JSON_THROW_ON_ERROR)) {
+            '[]' => '{}',
+            default => $casted,
+        };
+    }
+}

tests/Eloquent/JsonForceEmptyObjectAsArrayCastTest.php

@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tpetry\PostgresqlEnhanced\Tests\Eloquent;
+
+use Composer\Semver\Comparator;
+use Illuminate\Database\Eloquent\Model;
+use Tpetry\PostgresqlEnhanced\Eloquent\Casts\JsonForceEmptyObjectAsArray;
+use Tpetry\PostgresqlEnhanced\Tests\TestCase;
+
+class JsonForceEmptyObjectAsArrayCastTest extends TestCase
+{
+    public function testParseFromDatabaseValue(): void
+    {
+        if (Comparator::lessThan($this->app->version(), '8.0.0')) {
+            $this->markTestSkipped('Cast classes have been added with Laravel 8.');
+        }
+
+        $cast = new JsonForceEmptyObjectAsArray();
+        $model = new class extends Model { };
+
+        $this->assertNull($cast->get($model, 'column', null, []));
+        $this->assertEquals([], $cast->get($model, 'column', '{}', []));
+        $this->assertEquals(['a' => 1, 'b' => 2], $cast->get($model, 'column', '{"a":1,"b":2}', []));
+        $this->assertEquals(['c' => [1, 2, 3], 'd' => [4, 5, 6]], $cast->get($model, 'column', '{"c":[1,2,3],"d":[4,5,6]}', []));
+        $this->assertEquals([1, 2], $cast->get($model, 'column', '[1,2]', []));
+        $this->assertEquals([[1, 2, 3], [4, 5, 6]], $cast->get($model, 'column', '[[1,2,3],[4,5,6]]', []));
+    }
+
+    public function testTransformToDatabaseValue(): void
+    {
+        if (Comparator::lessThan($this->app->version(), '8.0.0')) {
+            $this->markTestSkipped('Cast classes have been added with Laravel 8.');
+        }
+
+        $cast = new JsonForceEmptyObjectAsArray();
+        $model = new class extends Model { };
+
+        $this->assertNull($cast->get($model, 'column', null, []));
+
+        $this->assertEquals('{}', $cast->set($model, 'column', [], []));
+        $this->assertEquals('{"a":1,"b":2}', $cast->set($model, 'column', ['a' => 1, 'b' => 2], []));
+        $this->assertEquals('{"c":[1,2,3],"d":[4,5,6]}', $cast->set($model, 'column', ['c' => [1, 2, 3], 'd' => [4, 5, 6]], []));
+        $this->assertEquals('[1,2]', $cast->set($model, 'column', [1, 2], []));
+        $this->assertEquals('[[1,2,3],[4,5,6]]', $cast->set($model, 'column', [[1, 2, 3], [4, 5, 6]], []));
+
+        $this->assertEquals('{}', $cast->set($model, 'column', collect(), []));
+        $this->assertEquals('{"a":1,"b":2}', $cast->set($model, 'column', collect(['a' => 1, 'b' => 2]), []));
+        $this->assertEquals('{"c":[1,2,3],"d":[4,5,6]}', $cast->set($model, 'column', collect(['c' => [1, 2, 3], 'd' => [4, 5, 6]]), []));
+        $this->assertEquals('[1,2]', $cast->set($model, 'column', collect([1, 2]), []));
+        $this->assertEquals('[[1,2,3],[4,5,6]]', $cast->set($model, 'column', collect([[1, 2, 3], [4, 5, 6]]), []));
+    }
+}