Add ofType property to Connection and Edge types.

Connection type is some kind of wrapper under GraphQLNamedType.
This behavior needed for `graphql-compose` module in `projection` helper, otherwise it incorrectly construct projectionMapper for tricky fields.

Author: nodkz

src/types/__tests__/connectionType-test.js

@@ -36,6 +36,11 @@ describe('types/connectionType.js', () => {
       const cursor = getNamedType(tc.getFieldType('cursor'));
       expect(cursor).equal(GraphQLConnectionCursor);
     });
+
+    it('should have `ofType` property (like GraphQLList, GraphQLNonNull)', () => {
+      const edgeType = prepareEdgeType(userTypeComposer);
+      expect(edgeType).property('ofType').equals(userTypeComposer.getType());
+    });
   });
 
   describe('prepareConnectionType()', () => {
@@ -69,5 +74,12 @@ describe('types/connectionType.js', () => {
       const edges = getNamedType(tc.getFieldType('edges'));
       expect(edges).property('name').equals('UserEdge');
     });
+
+    it('should have `ofType` property (like GraphQLList, GraphQLNonNull)', () => {
+      // this behavior needed for `graphql-compose` module in `projection` helper
+      // otherwise it incorrectly construct projectionMapper for tricky fields
+      const connectionType = prepareConnectionType(userTypeComposer);
+      expect(connectionType).property('ofType').equals(userTypeComposer.getType());
+    });
   });
 });

src/types/connectionType.js

@@ -18,7 +18,7 @@ import PageInfoType from './pageInfoType';
 export function prepareEdgeType(typeComposer: TypeComposer): GraphQLObjectType {
   const name = `${typeComposer.getTypeName()}Edge`;
 
-  return new GraphQLObjectType({
+  const edgeType = new GraphQLObjectType({
     name,
     description: 'An edge in a connection.',
     fields: () => ({
@@ -32,13 +32,15 @@ export function prepareEdgeType(typeComposer: TypeComposer): GraphQLObjectType {
       },
     }),
   });
+  edgeType.ofType = typeComposer.getType();
+  return edgeType;
 }
 
 
 export function prepareConnectionType(typeComposer: TypeComposer): GraphQLObjectType {
   const name = `${typeComposer.getTypeName()}Connection`;
 
-  return new GraphQLObjectType({
+  const connectionType = new GraphQLObjectType({
     name,
     description: 'A connection to a list of items.',
     fields: () => ({
@@ -56,4 +58,6 @@ export function prepareConnectionType(typeComposer: TypeComposer): GraphQLObject
       },
     }),
   });
+  connectionType.ofType = typeComposer.getType();
+  return connectionType;
 }