import { MongoDataSource } from 'apollo-datasource-mongodb'
export default class LoaderAsset extends MongoDataSource {
 async getAsset(assetId) {
 return this.findOneById(assetId) // ERROR IS HERE
 }
}
async function startApolloServer(app) {
 const httpServer = http.createServer(app);
 
 const server = new ApolloServer({
 typeDefs,
 resolvers,
 plugins: [ApolloServerPluginDrainHttpServer({ httpServer })]
 
 });
 await server.start();
 app.use(
 '/graphql',
 cors(),
 bodyParser.json(),
 expressMiddleware(server, {
 context: async ({ req }) => {
 return {
 dataSources: {
 loaderAsset: new LoaderAsset(modelAsset),
 }
 }
 },
 }),
 );
 const port = config.get('Port') || 8081;
 await new Promise(resolve => httpServer.listen({ port }, resolve));
}