message: fix issues with object scalars resolvers
diff: @@ -926,10 +926,17 @@ export class GraphQLModule<Config = any, Session extends object = any, Context =
  return directiveResolvers;
  }
  + private _isScalarResolver(resolver: any): boolean {
  + return (
  + resolver instanceof GraphQLScalarType ||
  + (typeof resolver === 'object' && resolver['serialize'] && resolver['name'])
  + );
  + }
  +
  private addSessionInjectorToSelfResolversContext(resolvers: IResolvers<any, ModuleContext<Context>>) {
  for (const type in resolvers) {
  const typeResolvers = resolvers[type];
  - if (!(typeResolvers instanceof GraphQLScalarType)) {
  + if (!this._isScalarResolver(typeResolvers)) {
  for (const prop in resolvers[type]) {
  const resolver = typeResolvers[prop];
  if (typeof resolver === 'function') {
  