deferred props

Author: joetannenbaum

src/DeferProp.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace Inertia;
+
+use Illuminate\Support\Facades\App;
+
+class DeferProp
+{
+    protected $callback;
+
+    protected $group;
+
+    public function __construct(callable $callback, ?string $group = null)
+    {
+        $this->callback = $callback;
+        $this->group = $group;
+    }
+
+    public function group()
+    {
+        return $this->group;
+    }
+
+    public function __invoke()
+    {
+        return App::call($this->callback);
+    }
+}

src/Inertia.php

@@ -12,6 +12,7 @@
  * @method static void version(\Closure|string|null $version)
  * @method static string getVersion()
  * @method static \Inertia\LazyProp lazy(callable $callback)
+ * @method static \Inertia\DeferProp defer(callable $callback, string $group = 'default')
  * @method static \Inertia\AlwaysProp always(mixed $value)
  * @method static \Inertia\Response render(string $component, array|\Illuminate\Contracts\Support\Arrayable $props = [])
  * @method static \Symfony\Component\HttpFoundation\Response location(string|\Symfony\Component\HttpFoundation\RedirectResponse $url)

src/Response.php

@@ -114,7 +114,7 @@ public function resolveProperties(Request $request, array $props): array
 
         if (! $isPartial) {
             $props = array_filter($this->props, static function ($prop) {
-                return ! ($prop instanceof LazyProp);
+                return ! ($prop instanceof LazyProp) && ! ($prop instanceof DeferProp);
             });
         }
 
@@ -132,6 +132,21 @@ public function resolveProperties(Request $request, array $props): array
 
         $props = $this->resolvePropertyInstances($props, $request);
 
+        if (! $isPartial) {
+            $deferredProps = collect($this->props)->filter(function ($prop) {
+                return $prop instanceof DeferProp;
+            })->map(function ($prop, $key) {
+                return [
+                    'key' => $key,
+                    'group' => $prop->group(),
+                ];
+            })->groupBy('group')->map->pluck('key');
+
+            if ($deferredProps->isNotEmpty()) {
+                $props['deferred'] = $deferredProps->toArray();
+            }
+        }
+
         return $props;
     }
 

src/ResponseFactory.php

@@ -87,6 +87,11 @@ public function lazy(callable $callback): LazyProp
         return new LazyProp($callback);
     }
 
+    public function defer(callable $callback, string $group = 'default'): DeferProp
+    {
+        return new DeferProp($callback, $group);
+    }
+
     /**
      * @param  mixed  $value
      */

tests/DeferPropTest.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace Inertia\Tests;
+
+use Illuminate\Http\Request;
+use Inertia\DeferProp;
+
+class DeferPropTest extends TestCase
+{
+    public function test_can_invoke(): void
+    {
+        $deferProp = new DeferProp(function () {
+            return 'A lazy value';
+        });
+
+        $this->assertSame('A lazy value', $deferProp());
+    }
+
+    public function test_can_resolve_bindings_when_invoked(): void
+    {
+        $deferProp = new DeferProp(function (Request $request) {
+            return $request;
+        });
+
+        $this->assertInstanceOf(Request::class, $deferProp());
+    }
+}