fix(FieldsConverter): Pass fields with MongoID type in Embedded Schem…

…as (except _id)

src/__mocks__/contactsSchema.js

@@ -5,6 +5,7 @@ const ContactsSchema = new Schema(
     phones: [String],
     email: String,
     skype: String,
+    locationId: Schema.Types.ObjectId,
   }
 );
 

src/__tests__/fieldConverter-test.js

@@ -167,7 +167,12 @@ describe('fieldConverter', () => {
     });
 
     it('should have embedded fields', () => {
-      expect(embeddedFields.email).to.be.defined;
+      expect(embeddedFields.email).to.be.ok;
+    });
+
+    it('should have embedded fields with MongoID type, except pseudoID', () => {
+      expect(embeddedFields.locationId).to.be.ok;
+      expect(embeddedFields._id).to.be.undefined;
     });
 
     it('should skip pseudo mongoose _id field', () => {

src/fieldsConverter.js

@@ -231,8 +231,9 @@ export function deriveComplexType(field: MongooseFieldT): ComplexTypesT {
 function removePseudoIdField(typeComposer: TypeComposer): void {
   // remove pseudo object id mongoose field
   const gqFields = typeComposer.getFields();
-  Object.keys(gqFields).forEach((name) => {
-    if (gqFields[name].type === GraphQLMongoID) {
+  const pseudoFieldNames = ['_id'];
+  pseudoFieldNames.forEach((name) => {
+    if (gqFields[name] && gqFields[name].type === GraphQLMongoID) {
       typeComposer.removeField(name);
     }
   });