feat: allow constraining ToMany query

src/Laravel/EloquentBuffer.php

@@ -6,6 +6,8 @@
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\MorphTo;
 use Tobyz\JsonApiServer\Context;
+use Tobyz\JsonApiServer\Laravel\Field\ToMany;
+use Tobyz\JsonApiServer\Laravel\Field\ToOne;
 use Tobyz\JsonApiServer\Schema\Field\Relationship;
 
 abstract class EloquentBuffer
@@ -56,7 +58,21 @@ public static function load(
                     $modelClass = get_class($resource->newModel($context));
 
                     if ($resource instanceof EloquentResource && !isset($constrain[$modelClass])) {
-                        $constrain[$modelClass] = fn($query) => $resource->scope($query, $context);
+                        $constrain[$modelClass] = function ($query) use (
+                            $resource,
+                            $context,
+                            $relationship,
+                        ) {
+                            $resource->scope($query, $context);
+
+                            if (
+                                ($relationship instanceof ToMany ||
+                                    $relationship instanceof ToOne) &&
+                                $relationship->scope
+                            ) {
+                                ($relationship->scope)($query, $context);
+                            }
+                        };
                     }
                 }
 

src/Laravel/Field/Concerns/ScopesRelationship.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace Tobyz\JsonApiServer\Laravel\Field\Concerns;
+
+use Closure;
+
+trait ScopesRelationship
+{
+    public ?Closure $scope = null;
+
+    public function scope(?Closure $scope): static
+    {
+        $this->scope = $scope;
+
+        return $this;
+    }
+}

src/Laravel/Field/ToMany.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace Tobyz\JsonApiServer\Laravel\Field;
+
+use Tobyz\JsonApiServer\Schema\Field\ToMany as BaseToMany;
+
+class ToMany extends BaseToMany
+{
+    use Concerns\ScopesRelationship;
+}

src/Laravel/Field/ToOne.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace Tobyz\JsonApiServer\Laravel\Field;
+
+use Tobyz\JsonApiServer\Schema\Field\ToOne as BaseToOne;
+
+class ToOne extends BaseToOne
+{
+    use Concerns\ScopesRelationship;
+}

src/Schema/Field/ToMany.php

@@ -2,6 +2,7 @@
 
 namespace Tobyz\JsonApiServer\Schema\Field;
 
+use Closure;
 use Tobyz\JsonApiServer\Context;
 use Tobyz\JsonApiServer\Exception\BadRequestException;
 use Tobyz\JsonApiServer\Exception\Sourceable;