testing registering a connection to an interface that other interfaces implement

register-connection-to-interfaces.php

add_action( 'graphql_register_types', function() {

	register_graphql_field( 'RootQuery', 'testType', [
		'type' => 'TestType',
		'resolve' => function() {
			return [
				'__typename' => 'TestType',
				'test' => 'Test Field Value...',
				'id' => 'root:testType:1'
			];
		}
	] );

	register_graphql_interface_type( 'TestInterfaceB', [
		'description' => 'Test Interface B',
		'fields' => [
			'interfaceBTestField' => [
				'type' => 'String',
				'description' => 'Test Field defined on the TestInterfaceB',
			],
		],
	]);

	register_graphql_interface_type( 'TestInterface', [
		'description' => 'Test Interface',
		'interfaces' => [ 'TestInterfaceB' ],
		'fields' => [
			'interfaceTestField' => [
				'type' => 'String',
				'description' => 'Test Field defined on the TestInterface',
			],
		],
	]);

	register_graphql_object_type( 'TestType', [
		'interfaces' => [ 'TestInterface', 'Node' ],
		'description' => 'Test type',
		'fields' => [
			'test' => [
				'type' => 'String',
				'description' => 'Test Field',
			],
		],
	] );

	register_graphql_connection([
		'fromType' => 'TestInterfaceB',
		'toType' => 'TestType',
		'fromFieldName' => 'testInterfaceBToTestTypeConnection',
		'resolve' => function() {
			return [
				'nodes' => [
					[
						'__typename' => 'TestType',
						'id' => 'test:id:1',
						'test' => 'test value',
						'interfaceTestField' => 'interface test value'
					],
					[
						'__typename' => 'TestType',
						'id' => 'test:id:2',
						'test' => 'test value',
						'interfaceTestField' => 'interface test value'
					]
				]
			];
		}
	]);

});