Store generated TypeComposer from mongoose model in mongoose object, for further reusing if needed.

Sometimes one model/schema can be used in different model. So if it already generated, then we should use this unique instance.

Author: nodkz

src/definition.js

@@ -1,6 +1,7 @@
 /* @flow */
 /* eslint-disable */
 
+import type { TypeComposer } from 'graphql-compose';
 import type { connectionSortMapOpts as _connectionSortMapOpts} from 'graphql-compose-connection/lib/definition';
 export type connectionSortMapOpts = _connectionSortMapOpts;
 
@@ -22,6 +23,7 @@ export type MonooseModelIndex = [
 ];
 
 export type MongooseModelT = {
+  _gqcTypeComposer: TypeComposer,
   modelName: string,
   schema: MongooseModelSchemaT,
   create(doc: Object | Object[]): Promise<Object>,

src/fieldsConverter.js

@@ -126,6 +126,10 @@ export function convertModelToGraphQL(
     + '`name` argument should be non-empty string.');
   }
 
+  if (model._gqcTypeComposer) {
+    return model._gqcTypeComposer;
+  }
+
   const typeComposer = new TypeComposer(
     new GraphQLObjectType({
       name: typeName,
@@ -135,6 +139,8 @@ export function convertModelToGraphQL(
     })
   );
 
+  model._gqcTypeComposer = typeComposer; // eslint-disable-line
+
   const mongooseFields = getFieldsFromModel(model, typeName);
   const graphqlFields = {};