livewire · oli-laban · Dec 12, 2024
diff --git a/src/Attributes/Required.php b/src/Attributes/Required.php
@@ -0,0 +1,12 @@
+<?php
+
+namespace Livewire\Attributes;
+
+use Attribute;
+use Livewire\Features\SupportRequiredProperties\BaseRequired;
+
+#[Attribute(Attribute::TARGET_PROPERTY)]
+class Required extends BaseRequired
+{
+    //
+}
diff --git a/src/Features/SupportRequiredProperties/BaseRequired.php b/src/Features/SupportRequiredProperties/BaseRequired.php
@@ -0,0 +1,12 @@
+<?php
+
+namespace Livewire\Features\SupportRequiredProperties;
+
+use Attribute;
+use Livewire\Features\SupportAttributes\Attribute as LivewireAttribute;
+
+#[Attribute(Attribute::TARGET_PROPERTY)]
+class BaseRequired extends LivewireAttribute
+{
+    //
+}
diff --git a/src/Features/SupportRequiredProperties/RequiredPropertyNotProvidedException.php b/src/Features/SupportRequiredProperties/RequiredPropertyNotProvidedException.php
@@ -0,0 +1,18 @@
+<?php
+
+namespace Livewire\Features\SupportRequiredProperties;
+
+use Illuminate\Support\Str;
+
+class RequiredPropertyNotProvidedException extends \Exception
+{
+    public function __construct($componentName, $missingProperties)
+    {
+        parent::__construct(sprintf(
+            'Missing required %s [%s] in component [%s]',
+            Str::plural('property', $missingProperties->count()),
+            $missingProperties->implode(', '),
+            $componentName,
+        ));
+    }
+}
diff --git a/src/Features/SupportRequiredProperties/SupportRequiredProperties.php b/src/Features/SupportRequiredProperties/SupportRequiredProperties.php
@@ -0,0 +1,23 @@
+<?php
+
+namespace Livewire\Features\SupportRequiredProperties;
+
+use Livewire\ComponentHook;
+
+class SupportRequiredProperties extends ComponentHook
+{
+    public function mount($params)
+    {
+        $requiredProperties = $this->component
+            ->getAttributes()
+            ->whereInstanceOf(BaseRequired::class)
+            ->map(fn ($property) => $property->getName());
+
+        $missingProperties = $requiredProperties->diff(array_keys($params));
+
+        throw_if(
+            $missingProperties->count(),
+            new RequiredPropertyNotProvidedException($this->component->getName(), $missingProperties),
+        );
+    }
+}
diff --git a/src/Features/SupportRequiredProperties/UnitTest.php b/src/Features/SupportRequiredProperties/UnitTest.php
@@ -0,0 +1,64 @@
+<?php
+
+namespace Features\SupportRequiredProperties;
+
+use Livewire\Attributes\Required;
+use Livewire\Livewire;
+use Tests\TestCase;
+use Tests\TestComponent;
+
+class UnitTest extends TestCase
+{
+    public function test_unprovided_required_property_triggers_exception()
+    {
+        $this->expectExceptionMessageMatches(
+            '/Missing required property \[foo] in component \[.*]/',
+        );
+
+        Livewire::test(new class extends TestComponent {
+            #[Required]
+            public string $foo;
+        });
+    }
+
+    public function test_multiple_unprovided_required_properties_triggers_exception()
+    {
+        $this->expectExceptionMessageMatches(
+            '/Missing required properties \[foo, bar] in component \[.*]/',
+        );
+
+        Livewire::test(new class extends TestComponent {
+            #[Required]
+            public string $foo;
+
+            #[Required]
+            public string $bar;
+        });
+    }
+
+    public function test_providing_required_properties_renders_component()
+    {
+        Livewire::test(new class extends TestComponent {
+            #[Required]
+            public string $foo;
+
+            #[Required]
+            public string $bar;
+        }, ['foo' => '1', 'bar' => '2'])
+            ->assertOk()
+            ->assertSetStrict('foo', '1')
+            ->assertSetStrict('bar', '2');
+    }
+
+    public function test_provided_required_properties_with_incorrect_types_are_still_applied()
+    {
+        $this->expectExceptionMessage(
+            'Cannot assign null to property Tests\TestComponent@anonymous::$foo of type string',
+        );
+
+        Livewire::test(new class extends TestComponent {
+            #[Required]
+            public string $foo;
+        }, ['foo' => null]);
+    }
+}
diff --git a/src/LivewireServiceProvider.php b/src/LivewireServiceProvider.php
@@ -87,6 +87,7 @@ protected function bootFeatures()
             Features\SupportNestedComponentListeners\SupportNestedComponentListeners::class,
             Features\SupportMorphAwareIfStatement\SupportMorphAwareIfStatement::class,
             Features\SupportAutoInjectedAssets\SupportAutoInjectedAssets::class,
+            Features\SupportRequiredProperties\SupportRequiredProperties::class,
             Features\SupportComputed\SupportLegacyComputedPropertySyntax::class,
             Features\SupportNestingComponents\SupportNestingComponents::class,
             Features\SupportScriptsAndAssets\SupportScriptsAndAssets::class,