Unexpected <EOF>: Can a graphql file only import other files and do nothing else?

I am using apollo-server-express to run my GraphQL server with a prisma database. My main schema is listed below, which just uses graphql-tag/loader to import other .graphql files. When I try to run my server locally, I get the following message:

Error: Module build failed (from ./node_modules/graphql-tag/loader.js): GraphQLError: Syntax Error: Unexpected

Clearly, GraphQL wants schema/schema.graphql to declare some types, etc. Is there a way I can get around this so that I can have a .graphql file that all it does is import other .graphql files?

schema/schema.graphql:

#import '../generated/prisma.graphql'
#import './secondSchema.graphql'

index.js:

import http from 'http';
import express from 'express';
import { ApolloServer } from 'apollo-server-express';
import resolvers from './schema/resolvers';
import schema from './schema/schema.graphql';
import prisma from './prisma';

const server = new ApolloServer({
  context: {
    prisma,
  },
  resolvers,
  typeDefs: schema,
});

const app = express();
server.applyMiddleware({ app });

const PORT = 5000;

const httpServer = http.createServer(app);
server.installSubscriptionHandlers(httpServer);

httpServer.listen(PORT, () => {
  console.log(`Server ready at http://localhost:${PORT}${server.graphqlPath}`);
  console.log(`Subscriptions ready at ws://localhost:${PORT}${server.subscriptionsPath}`);
});

if (module.hot) {
  module.hot.accept();
  module.hot.dispose(() => server.stop());
}

You can add a "dummy" or placeholder type that's not actually used anywhere so that the parser doesn't complain. However, the simpler fix would be to stop importing the other type definition files into one file and just pass all of them to typeDefs as an array.

const server = new ApolloServer({
  context: {
    prisma,
  },
  resolvers,
  typeDefs: [prismaTypeDefs, someOtherTypeDefs],
});