feat: introduce ObjectBuilder::addField() (#125)

Author: simPod

src/Builder/ObjectBuilder.php

@@ -8,6 +8,8 @@
 use GraphQL\Type\Definition\InterfaceType;
 use GraphQL\Type\Definition\ResolveInfo;
 
+use function is_callable;
+
 class ObjectBuilder extends TypeBuilder
 {
     /** @var InterfaceType[] */
@@ -49,6 +51,30 @@ public function setFields(callable|array $fields): self
         return $this;
     }
 
+    /**
+     * @param FieldDefinition|array<string, mixed> $field
+     *
+     * @return $this
+     */
+    public function addField(FieldDefinition|array $field): self
+    {
+        if (is_callable($this->fields)) {
+            $originalFields = $this->fields;
+            /** @var callable():array<FieldDefinition|array<string, mixed>> $closure */
+            $closure      = static function () use ($field, $originalFields): array {
+                $originalFields   = $originalFields();
+                $originalFields[] = $field;
+
+                return $originalFields;
+            };
+            $this->fields = $closure;
+        } else {
+            $this->fields[] =  $field;
+        }
+
+        return $this;
+    }
+
     /**
      * @param callable(mixed, array<mixed>, mixed, ResolveInfo) : mixed $fieldResolver
      *

tests/Builder/ObjectBuilderTest.php

@@ -54,6 +54,36 @@ public function __construct()
         self::assertCount(2, $object['fields']);
     }
 
+    public function testAddFields(): void
+    {
+        $builder = ObjectBuilder::create('Name');
+        $object  = $builder
+            ->setFields([
+                FieldBuilder::create('SomeField', Type::string())->build(),
+            ])
+            ->addField(FieldBuilder::create('Foo', Type::string())->build())
+            ->build();
+
+        self::assertIsArray($object['fields']);
+        self::assertCount(2, $object['fields']);
+    }
+
+    public function testAddFieldsToCallable(): void
+    {
+        $builder = ObjectBuilder::create('Name');
+        $object  = $builder
+            ->setFields(static fn () => [
+                FieldBuilder::create('SomeField', Type::string())->build(),
+            ])
+            ->addField(FieldBuilder::create('Foo', Type::string())->build())
+            ->build();
+
+        self::assertIsCallable($object['fields']);
+        /** @var array<FieldDefinition|array<string, mixed>> $fields */
+        $fields = $object['fields']();
+        self::assertCount(2, $fields);
+    }
+
     public function testInvalidName(): void
     {
         $this->expectException(InvalidArgument::class);