Mapping Executor

README.md

@@ -278,11 +278,12 @@ Option | Type | Notes
 name | `string` | Required. Name of the field. If not set - GraphQL will look use `key` of fields array on type definition.
 type | `Type` or `callback() => Type` | Required. One of internal or custom types. Alternatively - callback that returns `type`.
 args | `array` | Array of possible type arguments. Each entry is expected to be an array with following keys: **name** (`string`), **type** (`Type` or `callback() => Type`), **defaultValue** (`any`)
-resolve | `callback($value, $args, ResolveInfo $info) => $data` | Function that receives `$value` describing parent type and returns `$data` for this field.
+resolve | `callback($value, $args, ResolveInfo $info) => $fieldValue` | Function that receives `$value` of parent type and returns value for this field. Mutually exclusive with `map`
+map | `callback($listOfValues, $args, ResolveInfo $info) => $fieldValues[]` | Function that receives list of parent type values and maps them to list of field values. Mutually exclusive with `resolve`
 description | `string` | Field description for clients
 deprecationReason | `string` | Text describing why this field is deprecated. When not empty - field will not be returned by introspection queries (unless forced)
 
-The `resolve` option is exactly the place where your custom fetching logic lives.
+Use `map` or `resolve` for custom data fetching logic. `resolve` is easier to use, but `map` allows batching of queries to backend storage (for example you can use Redis MGET or IN(?) for SQL queries).
 
 
 ### Schema

src/Executor/Executor.php

@@ -147,10 +147,12 @@ class Executor
         $fields = self::collectFields($exeContext, $type, $operation->selectionSet, new \ArrayObject(), new \ArrayObject());
 
         if ($operation->operation === 'mutation') {
-            return self::executeFieldsSerially($exeContext, $type, $rootValue, $fields->getArrayCopy());
+            $result = self::executeFieldsSerially($exeContext, $type, [$rootValue], $fields);
+        } else {
+            $result = self::executeFields($exeContext, $type, [$rootValue], $fields);
         }
 
-        return self::executeFields($exeContext, $type, $rootValue, $fields);
+        return null === $result || $result === [] ? [] : $result[0];
     }
 
 
@@ -187,30 +189,40 @@ class Executor
     /**
      * Implements the "Evaluating selection sets" section of the spec
      * for "write" mode.
+     *
+     * @param ExecutionContext $exeContext
+     * @param ObjectType $parentType
+     * @param $sourceList
+     * @param $sourceIsList
+     * @param $fields
+     * @return array
+     * @throws Error
+     * @throws \Exception
      */
-    private static function executeFieldsSerially(ExecutionContext $exeContext, ObjectType $parentType, $sourceValue, $fields)
+    private static function executeFieldsSerially(ExecutionContext $exeContext, ObjectType $parentType, $sourceList, $fields)
     {
         $results = [];
         foreach ($fields as $responseName => $fieldASTs) {
-            $result = self::resolveField($exeContext, $parentType, $sourceValue, $fieldASTs);
+            self::resolveField($exeContext, $parentType, $sourceList, $fieldASTs, $responseName, $results);
+        }
 
-            if ($result !== self::$UNDEFINED) {
-                // Undefined means that field is not defined in schema
-                $results[$responseName] = $result;
-            }
-        }
         return $results;
     }
 
     /**
      * Implements the "Evaluating selection sets" section of the spec
      * for "read" mode.
+     * @param ExecutionContext $exeContext
+     * @param ObjectType $parentType
+     * @param $sourceList
+     * @param $fields
+     * @return array
      */
-    private static function executeFields(ExecutionContext $exeContext, ObjectType $parentType, $source, $fields)
+    private static function executeFields(ExecutionContext $exeContext, ObjectType $parentType, $sourceList, $fields)
     {
         // Native PHP doesn't support promises.
         // Custom executor should be built for platforms like ReactPHP
-        return self::executeFieldsSerially($exeContext, $parentType, $source, $fields);
+        return self::executeFieldsSerially($exeContext, $parentType, $sourceList, $fields);
     }
 
 
@@ -345,12 +357,21 @@ class Executor
     }
 
     /**
-     * Resolves the field on the given source object. In particular, this
-     * figures out the value that the field returns by calling its resolve function,
-     * then calls completeValue to complete promises, serialize scalars, or execute
-     * the sub-selection-set for objects.
+     * Given list of parent type values returns corresponding list of field values
+     *
+     * In particular, this
+     * figures out the value that the field returns by calling its `resolve` or `map` function,
+     * then calls `completeValue` on each value to serialize scalars, or execute the sub-selection-set
+     * for objects.
+     *
+     * @param ExecutionContext $exeContext
+     * @param ObjectType $parentType
+     * @param $sourceValueList
+     * @param $fieldASTs
+     * @return array
+     * @throws Error
      */
-    private static function resolveField(ExecutionContext $exeContext, ObjectType $parentType, $source, $fieldASTs)
+    private static function resolveField(ExecutionContext $exeContext, ObjectType $parentType, $sourceValueList, $fieldASTs, $responseName, &$resolveResult)
     {
         $fieldAST = $fieldASTs[0];
         $fieldName = $fieldAST->name->value;
@@ -358,19 +379,11 @@ class Executor
         $fieldDef = self::getFieldDef($exeContext->schema, $parentType, $fieldName);
 
         if (!$fieldDef) {
-            return self::$UNDEFINED;
+            return ;
         }
 
         $returnType = $fieldDef->getType();
 
-        if (isset($fieldDef->resolve)) {
-            $resolveFn = $fieldDef->resolve;
-        } else if (isset($parentType->resolveField)) {
-            $resolveFn = $parentType->resolveField;
-        } else {
-            $resolveFn = self::$defaultResolveFn;
-        }
-
         // Build hash of arguments from the field.arguments AST, using the
         // variables scope to fulfill any variable references.
         // TODO: find a way to memoize, in case this field is within a List type.
@@ -394,12 +407,22 @@ class Executor
             'variableValues' => $exeContext->variableValues,
         ]);
 
-        // If an error occurs while calling the field `resolve` function, ensure that
+        $mapFn = $fieldDef->mapFn;
+
+        // If an error occurs while calling the field `map` or `resolve` function, ensure that
         // it is wrapped as a GraphQLError with locations. Log this error and return
         // null if allowed, otherwise throw the error so the parent field can handle
         // it.
+        if ($mapFn) {
             try {
-            $result = call_user_func($resolveFn, $source, $args, $info);
+                $mapped = call_user_func($mapFn, $sourceValueList, $args, $info);
+
+                Utils::invariant(
+                    is_array($mapped) && count($mapped) === count($sourceValueList),
+                    "Function `map` of $parentType.$fieldName is expected to return array " .
+                    "with exact same number of items as list being mapped (first argument of `map`)"
+                );
+
             } catch (\Exception $error) {
                 $reportedError = Error::createLocatedError($error, $fieldASTs);
 
@@ -411,14 +434,48 @@ class Executor
                 return null;
             }
 
-        return self::completeValueCatchingError(
+            foreach ($mapped as $index => $value) {
+                $resolveResult[$index][$responseName] = self::completeValueCatchingError(
                     $exeContext,
                     $returnType,
                     $fieldASTs,
                     $info,
-            $result
+                    $value
                 );
             }
+        } else {
+            if (isset($fieldDef->resolveFn)) {
+                $resolveFn = $fieldDef->resolveFn;
+            } else if (isset($parentType->resolveFieldFn)) {
+                $resolveFn = $parentType->resolveFieldFn;
+            } else {
+                $resolveFn = self::$defaultResolveFn;
+            }
+
+            foreach ($sourceValueList as $index => $value) {
+                try {
+                    $resolved = call_user_func($resolveFn, $value, $args, $info);
+                } catch (\Exception $error) {
+                    $reportedError = Error::createLocatedError($error, $fieldASTs);
+
+                    if ($returnType instanceof NonNull) {
+                        throw $reportedError;
+                    }
+
+                    $exeContext->addError($reportedError);
+                    $resolved = null;
+                }
+
+                $resolveResult[$index][$responseName] = self::completeValueCatchingError(
+                    $exeContext,
+                    $returnType,
+                    $fieldASTs,
+                    $info,
+                    $resolved
+                );
+            }
+        }
+    }
 
 
     public static function completeValueCatchingError(
@@ -489,14 +546,100 @@ class Executor
             return null;
         }
 
-        // If field type is List, complete each item in the list with the inner type
+        // If field type is Scalar or Enum, serialize to a valid value, returning
+        // null if serialization is not possible.
+        if ($returnType instanceof ScalarType ||
+            $returnType instanceof EnumType) {
+            return $returnType->serialize($result);
+        }
+
+        // If field type is List, and return type is Composite - complete by executing these fields with list value as parameter
         if ($returnType instanceof ListOfType) {
             $itemType = $returnType->getWrappedType();
+
             Utils::invariant(
                 is_array($result) || $result instanceof \Traversable,
                 'User Error: expected iterable, but did not find one.'
             );
 
+            // For Object[]:
+            // Allow all object fields to process list value in it's `map` callback:
+            if ($itemType instanceof ObjectType) {
+                // Filter out nulls (as `map` doesn't expect it):
+                $list = [];
+                foreach ($result as $index => $item) {
+                    if (null !== $item) {
+                        $list[] = $item;
+                    }
+                }
+
+                $subFieldASTs = self::collectSubFields($exeContext, $itemType, $fieldASTs);
+                $mapped = self::executeFields($exeContext, $itemType, $list, $subFieldASTs);
+
+                $i = 0;
+                $completed = [];
+                foreach ($result as $index => $item) {
+                    if (null === $item) {
+                        // Complete nulls separately
+                        $completed[] = self::completeValueCatchingError($exeContext, $itemType, $fieldASTs, $info, $item);
+                    } else {
+                        // Assuming same order of mapped values
+                        $completed[] = $mapped[$i++];
+                    }
+                }
+                return $completed;
+
+            } else if ($itemType instanceof AbstractType) {
+
+                // Values sharded by ObjectType
+                $listPerObjectType = [];
+
+                // Helper structures to restore ordering after resolve calls
+                $resultTypeMap = [];
+                $typeNameMap = [];
+                $cursors = [];
+
+                foreach ($result as $index => $item) {
+                    if (null !== $item) {
+                        $objectType = $itemType->getObjectType($item, $info);
+
+                        if ($objectType && !$itemType->isPossibleType($objectType)) {
+                            $exeContext->addError(new Error(
+                                "Runtime Object type \"$objectType\" is not a possible type for \"$itemType\"."
+                            ));
+                            $result[$index] = null;
+                        } else {
+                            $listPerObjectType[$objectType->name][] = $item;
+                            $resultTypeMap[$index] = $objectType->name;
+                            $typeNameMap[$objectType->name] = $objectType;
+                        }
+                    }
+                }
+
+                $mapped = [];
+                foreach ($listPerObjectType as $typeName => $list) {
+                    $objectType = $typeNameMap[$typeName];
+                    $subFieldASTs = self::collectSubFields($exeContext, $objectType, $fieldASTs);
+                    $mapped[$typeName] = self::executeFields($exeContext, $objectType, $list, $subFieldASTs);
+                    $cursors[$typeName] = 0;
+                }
+
+                // Restore order:
+                $completed = [];
+                foreach ($result as $index => $item) {
+                    if (null === $item) {
+                        // Complete nulls separately
+                        $completed[] = self::completeValueCatchingError($exeContext, $itemType, $fieldASTs, $info, $item);
+                    } else {
+                        $typeName = $resultTypeMap[$index];
+                        $completed[] = $mapped[$typeName][$cursors[$typeName]++];
+                    }
+                }
+
+                return $completed;
+            } else {
+
+                // For simple lists:
                 $tmp = [];
                 foreach ($result as $item) {
                     $tmp[] = self::completeValueCatchingError($exeContext, $itemType, $fieldASTs, $info, $item);
@@ -504,17 +647,11 @@ class Executor
                 return $tmp;
             }
 
-        // If field type is Scalar or Enum, serialize to a valid value, returning
-        // null if serialization is not possible.
-        if ($returnType instanceof ScalarType ||
-            $returnType instanceof EnumType) {
-            Utils::invariant(method_exists($returnType, 'serialize'), 'Missing serialize method on type');
-            return $returnType->serialize($result);
         }
 
-        // Field type must be Object, Interface or Union and expect sub-selections.
         if ($returnType instanceof ObjectType) {
             $objectType = $returnType;
+
         } else if ($returnType instanceof AbstractType) {
             $objectType = $returnType->getObjectType($result, $info);
 
@@ -542,6 +679,18 @@ class Executor
         }
 
         // Collect sub-fields to execute to complete this value.
+        $subFieldASTs = self::collectSubFields($exeContext, $objectType, $fieldASTs);
+        return self::executeFields($exeContext, $objectType, [$result], $subFieldASTs)[0];
+    }
+
+    /**
+     * @param ExecutionContext $exeContext
+     * @param ObjectType $objectType
+     * @param $fieldASTs
+     * @return \ArrayObject
+     */
+    private static function collectSubFields(ExecutionContext $exeContext, ObjectType $objectType, $fieldASTs)
+    {
         $subFieldASTs = new \ArrayObject();
         $visitedFragmentNames = new \ArrayObject();
         for ($i = 0; $i < count($fieldASTs); $i++) {
@@ -556,11 +705,9 @@ class Executor
                 );
             }
         }
-
-        return self::executeFields($exeContext, $objectType, $result, $subFieldASTs);
+        return $subFieldASTs;
     }
 
-
     /**
      * If a resolve function is not given, then a default resolve behavior is used
      * which takes the property of the source object of the same name as the field

src/Type/Definition/FieldDefinition.php

@@ -23,13 +23,20 @@ class FieldDefinition
     public $args;
 
     /**
-     * source?: any,
-     * args?: ?{[argName: string]: any},
-     * info
+     * Callback for resolving field value given parent value.
+     * Mutually exclusive with `map`
      *
      * @var callable
      */
-    public $resolve;
+    public $resolveFn;
+
+    /**
+     * Callback for mapping list of parent values to list of field values.
+     * Mutually exclusive with `resolve`
+     *
+     * @var callable
+     */
+    public $mapFn;
 
     /**
      * @var string|null
@@ -62,6 +69,7 @@ class FieldDefinition
                 'defaultValue' => Config::ANY
             ], Config::KEY_AS_NAME),
             'resolve' => Config::CALLBACK,
+            'map' => Config::CALLBACK,
             'description' => Config::STRING,
             'deprecationReason' => Config::STRING,
         ]);
@@ -97,7 +105,8 @@ class FieldDefinition
     {
         $this->name = $config['name'];
         $this->type = $config['type'];
-        $this->resolve = isset($config['resolve']) ? $config['resolve'] : null;
+        $this->resolveFn = isset($config['resolve']) ? $config['resolve'] : null;
+        $this->mapFn = isset($config['map']) ? $config['map'] : null;
         $this->args = isset($config['args']) ? FieldArgument::createMap($config['args']) : [];
 
         $this->description = isset($config['description']) ? $config['description'] : null;

src/Type/Definition/InterfaceType.php

@@ -26,7 +26,7 @@ class InterfaceType extends Type implements AbstractType, OutputType, CompositeT
     /**
      * @var callback
      */
-    private $_resolveType;
+    private $_resolveTypeFn;
 
     /**
      * Update the interfaces to know about this implementation.
@@ -52,14 +52,14 @@ class InterfaceType extends Type implements AbstractType, OutputType, CompositeT
                 FieldDefinition::getDefinition(),
                 Config::KEY_AS_NAME
             ),
-            'resolveType' => Config::CALLBACK,
+            'resolveType' => Config::CALLBACK, // function($value, ResolveInfo $info) => ObjectType
             'description' => Config::STRING
         ]);
 
         $this->name = $config['name'];
         $this->description = isset($config['description']) ? $config['description'] : null;
         $this->_fields = !empty($config['fields']) ? FieldDefinition::createMap($config['fields']) : [];
-        $this->_resolveType = isset($config['resolveType']) ? $config['resolveType'] : null;
+        $this->_resolveTypeFn = isset($config['resolveType']) ? $config['resolveType'] : null;
     }
 
     /**
@@ -104,7 +104,7 @@ class InterfaceType extends Type implements AbstractType, OutputType, CompositeT
      */
     public function getObjectType($value, ResolveInfo $info)
     {
-        $resolver = $this->_resolveType;
+        $resolver = $this->_resolveTypeFn;
         return $resolver ? call_user_func($resolver, $value, $info) : Type::getTypeOf($value, $info, $this);
     }
 }

src/Type/Definition/ObjectType.php

@@ -69,7 +69,7 @@ class ObjectType extends Type implements OutputType, CompositeType
     /**
      * @var callable
      */
-    public $resolveField;
+    public $resolveFieldFn;
 
     public function __construct(array $config)
     {
@@ -77,7 +77,7 @@ class ObjectType extends Type implements OutputType, CompositeType
 
         $this->name = $config['name'];
         $this->description = isset($config['description']) ? $config['description'] : null;
-        $this->resolveField = isset($config['resolveField']) ? $config['resolveField'] : null;
+        $this->resolveFieldFn = isset($config['resolveField']) ? $config['resolveField'] : null;
         $this->_config = $config;
 
         if (isset($config['interfaces'])) {

src/Type/Definition/UnionType.php

@@ -25,7 +25,7 @@ class UnionType extends Type implements AbstractType, OutputType, CompositeType
         Config::validate($config, [
             'name' => Config::STRING | Config::REQUIRED,
             'types' => Config::arrayOf(Config::OBJECT_TYPE | Config::REQUIRED),
-            'resolveType' => Config::CALLBACK,
+            'resolveType' => Config::CALLBACK, // function($value, ResolveInfo $info) => ObjectType
             'description' => Config::STRING
         ]);
 
@@ -66,16 +66,19 @@ class UnionType extends Type implements AbstractType, OutputType, CompositeType
                 $this->_possibleTypeNames[$possibleType->name] = true;
             }
         }
-        return $this->_possibleTypeNames[$type->name] === true;
+        return isset($this->_possibleTypeNames[$type->name]);
     }
 
     /**
      * @param ObjectType $value
+     * @param ResolveInfo $info
+     *
      * @return Type
+     * @throws \Exception
      */
     public function getObjectType($value, ResolveInfo $info)
     {
         $resolver = $this->_resolveType;
-        return $resolver ? call_user_func($resolver, $value) : Type::getTypeOf($value, $info, $this);
+        return $resolver ? call_user_func($resolver, $value, $info) : Type::getTypeOf($value, $info, $this);
     }
 }

tests/Executor/ExecutorTest.php

@@ -6,9 +6,12 @@ use GraphQL\FormattedError;
 use GraphQL\Language\Parser;
 use GraphQL\Language\SourceLocation;
 use GraphQL\Schema;
-use GraphQL\Type\Definition\Config;
+use GraphQL\Type\Definition\InterfaceType;
 use GraphQL\Type\Definition\ObjectType;
+use GraphQL\Type\Definition\ResolveInfo;
 use GraphQL\Type\Definition\Type;
+use GraphQL\Type\Definition\UnionType;
+use GraphQL\Utils;
 
 class ExecutorTest extends \PHPUnit_Framework_TestCase
 {
@@ -164,11 +167,14 @@ class ExecutorTest extends \PHPUnit_Framework_TestCase
                 'c' => ['type' => Type::string(), 'resolve' => function () {
                     return 'Cherry';
                 }],
-                'deep' => ['type' => function () use (&$Type) {
+                'deep' => [
+                    'type' => function () use (&$Type) {
                         return $Type;
-                }, 'resolve' => function () {
+                    },
+                    'resolve' => function () {
                         return [];
-                }]
+                    }
+                ]
             ]
         ]);
         $schema = new Schema($Type);
@@ -503,72 +509,264 @@ class ExecutorTest extends \PHPUnit_Framework_TestCase
         ];
 
         $this->assertEquals($expected, $result->toArray());
-
-/*
-    var query = parse('{ field(a: true, c: false, e: 0) }');
-    var result = await execute(schema, query);
-
-    expect(result).to.deep.equal({
-      data: {
-        field: '{"a":true,"c":false,"e":0}'
-      }
-    });
-  });
-
-  it('fails when an isTypeOf check is not met', async () => {
-    class Special {
-      constructor(value) {
-        this.value = value;
-      }
     }
 
-    class NotSpecial {
-      constructor(value) {
-        this.value = value;
-      }
-    }
+    public function testExecutesMapCallbacksIfSet()
+    {
+        $fooData = [
+            ['field' => '1'],
+            ['field' => null],
+            null,
+            ['field' => '4'],
+        ];
 
-    var SpecialType = new GraphQLObjectType({
-      name: 'SpecialType',
-      isTypeOf(obj) {
-        return obj instanceof Special;
-      },
-      fields: {
-        value: { type: GraphQLString }
-      }
-    });
+        $foo = new ObjectType([
+            'name' => 'Foo',
+            'fields' => [
+                'field' => [
+                    'type' => Type::string(),
+                    'map' => function($listOfFoo, $args, $resolveInfo) use ($fooData) {
 
-    var schema = new GraphQLSchema({
-      query: new GraphQLObjectType({
-        name: 'Query',
-        fields: {
-          specials: {
-            type: new GraphQLList(SpecialType),
-            resolve: rootValue => rootValue.specials
-          }
-        }
-      })
-    });
-
-    var query = parse('{ specials { value } }');
-    var value = {
-      specials: [ new Special('foo'), new NotSpecial('bar') ]
-    };
-    var result = await execute(schema, query, value);
-
-    expect(result.data).to.deep.equal({
-      specials: [
-        { value: 'foo' },
-        null
-      ]
-    });
-    expect(result.errors).to.have.lengthOf(1);
-    expect(result.errors).to.containSubset([
-      { message:
-          'Expected value of type "SpecialType" but got: [object Object].',
-        locations: [ { line: 1, column: 3 } ] }
+                        return Utils::map($listOfFoo, function($fooData) use ($args, $resolveInfo) {
+                            return json_encode([
+                                'value' => $fooData['field'] === null ? null : $fooData['field'] . 'x',
+                                'args' => $args,
+                                'gotResolveInfo' => $resolveInfo instanceof ResolveInfo
                             ]);
                         });
- */
+                    },
+                    'args' => [
+                        'a' => ['type' => Type::boolean()],
+                        'b' => ['type' => Type::boolean()],
+                        'c' => ['type' => Type::int()]
+                    ]
+                ]
+            ]
+        ]);
+
+        $bar = new ObjectType([
+            'name' => 'Bar',
+            'fields' => [
+                'foo' => [
+                    'type' => Type::listOf($foo),
+                    'resolve' => function() use ($fooData) {
+                        return $fooData;
+                    }
+                ]
+            ]
+        ]);
+
+        $schema = new Schema($bar);
+
+        $query = Parser::parse('{ foo { field(a: true, c: 0) } }');
+        $result = Executor::execute($schema, $query);
+
+        $expected = [
+            'data' => [
+                'foo' => [
+                    ['field' => '{"value":"1x","args":{"a":true,"c":0},"gotResolveInfo":true}'],
+                    ['field' => '{"value":null,"args":{"a":true,"c":0},"gotResolveInfo":true}'],
+                    null,
+                    ['field' => '{"value":"4x","args":{"a":true,"c":0},"gotResolveInfo":true}'],
+                ]
+            ]
+        ];
+
+        $this->assertEquals($expected, $result->toArray());
+    }
+
+    public function testRespectsListsOfAbstractTypeWhenResolvingViaMap()
+    {
+        $type1 = null;
+        $type2 = null;
+        $type3 = null;
+
+        $resolveType = function($value) use (&$type1, &$type2, &$type3) {
+            switch ($value['type']) {
+                case 'Type1':
+                    return $type1;
+                case 'Type2':
+                    return $type2;
+                case 'Type3':
+                default:
+                    return $type3;
+            }
+        };
+
+        $mapValues = function($typeValues, $args) {
+            return Utils::map($typeValues, function($value) use ($args) {
+                if (array_key_exists('foo', $value)) {
+                    return json_encode([
+                        'value' => $value,
+                        'args' => $args,
+                    ]);
+                } else {
+                    return null;
+                }
+            });
+        };
+
+        $interface = new InterfaceType([
+            'name' => 'SomeInterface',
+            'fields' => [
+                'foo' => ['type' => Type::string()],
+            ],
+            'resolveType' => $resolveType
+        ]);
+
+        $type1 = new ObjectType([
+            'name' => 'Type1',
+            'fields' => [
+                'foo' => [
+                    'type' => Type::string(),
+                    'map' => $mapValues
+                ]
+            ],
+            'interfaces' => [$interface]
+        ]);
+
+        $type2 = new ObjectType([
+            'name' => 'Type2',
+            'fields' => [
+                'foo' => [
+                    'type' => Type::string(),
+                    'map' => $mapValues
+                ]
+            ],
+            'interfaces' => [$interface]
+        ]);
+
+        $type3 = new ObjectType([
+            'name' => 'Type3',
+            'fields' => [
+                'bar' => [
+                    'type' => Type::listOf(Type::string()),
+                    'map' => function($type3Values, $args) {
+                        return Utils::map($type3Values, function($value) use ($args) {
+                            return [
+                                json_encode([
+                                    'value' => $value,
+                                    'args' => $args
+                                ])
+                            ];
+                        });
+                    }
+                ]
+            ]
+        ]);
+
+        $union = new UnionType([
+            'name' => 'SomeUnion',
+            'types' => [$type1, $type3],
+            'resolveType' => $resolveType
+        ]);
+
+        $complexType = new ObjectType([
+            'name' => 'ComplexType',
+            'fields' => [
+                'iface' => [
+                    'type' => $interface
+                ],
+                'ifaceList' => [
+                    'type' => Type::listOf($interface)
+                ],
+                'union' => [
+                    'type' => $union
+                ],
+                'unionList' => [
+                    'type' => Type::listOf($union)
+                ]
+            ]
+        ]);
+
+        $type1values = [
+            ['type' => 'Type1', 'foo' => 'str1'],
+            ['type' => 'Type1'],
+            ['type' => 'Type1', 'foo' => null],
+        ];
+
+        $type2values = [
+            ['type' => 'Type2', 'foo' => 'str1'],
+            ['type' => 'Type2', 'foo' => null],
+            ['type' => 'Type2'],
+        ];
+
+        $type3values = [
+            ['type' => 'Type3', 'bar' => ['str1', 'str2']],
+            ['type' => 'Type3', 'bar' => null],
+        ];
+
+        $complexTypeValues = [
+            'iface' => $type1values[0],
+            'ifaceList' => array_merge($type1values, $type2values),
+            'union' => $type3values[0],
+            'unionList' => array_merge($type1values, $type3values)
+        ];
+
+        $expected = [
+            'data' => [
+                'test' => [
+                    'iface' => ['foo' => json_encode(['value' => $type1values[0], 'args' => []])],
+                    'ifaceList' => [
+                        ['foo' => '{"value":{"type":"Type1","foo":"str1"},"args":[]}'],
+                        ['foo' => null],
+                        ['foo' => '{"value":{"type":"Type1","foo":null},"args":[]}'],
+                        ['foo' => '{"value":{"type":"Type2","foo":"str1"},"args":[]}'],
+                        ['foo' => '{"value":{"type":"Type2","foo":null},"args":[]}'],
+                        ['foo' => null],
+                    ],
+                    'union' => [
+                        'bar' => ['{"value":{"type":"Type3","bar":["str1","str2"]},"args":[]}']
+                    ],
+                    'unionList' => [
+                        ['foo' => '{"value":{"type":"Type1","foo":"str1"},"args":[]}'],
+                        ['foo' => null],
+                        ['foo' => '{"value":{"type":"Type1","foo":null},"args":[]}'],
+                        ['bar' => ['{"value":{"type":"Type3","bar":["str1","str2"]},"args":[]}']],
+                        ['bar' => ['{"value":{"type":"Type3","bar":null},"args":[]}']],
+                    ]
+                ]
+            ]
+        ];
+
+        $schema = new Schema(new ObjectType([
+            'name' => 'Query',
+            'fields' => [
+                'test' => [
+                    'type' => $complexType,
+                    'resolve' => function() use ($complexTypeValues) {
+                        return $complexTypeValues;
+                    }
+                ]
+            ]
+        ]));
+
+        $query = '{
+            test {
+                iface{foo},
+                ifaceList{foo}
+                union {
+                    ... on Type1 {
+                        foo
+                    }
+                    ... on Type3 {
+                        bar
+                    }
+                }
+                unionList {
+                    ... on Type1 {
+                        foo
+                    }
+                    ... on Type3 {
+                        bar
+                    }
+                }
+            }
+        }';
+
+        $query = Parser::parse($query);
+        $result = Executor::execute($schema, $query);
+
+        $this->assertEquals($expected, $result->toArray());
     }
 }