graphql.ts

// graphql.ts

import 'graphql-import-node';
import {makeExecutableSchema} from 'graphql-tools';
import {ApolloServer} from 'apollo-server-express';
import Knex from 'knex';
import Dataloader from 'dataloader';
import config from 'config';
import resolvers from './resolvers';
import * as typeDefs from './typeDefs.graphql';

const loaders = () => ({
  getLocationsByMerchantId: new Dataloader(async merchantIds => {
    const locations = await Knex(config.get('database'))('locations')
      .whereIn('merchantId', merchantIds);
    return merchantIds.map(merchantId => locations.find(location => location.merchantId === merchantId));
  }),
  getProductsByMerchantId: new Dataloader(async merchantIds => {
    const products = await Knex(config.get('database'))('products')
      .whereIn('merchantId', merchantIds);
    return merchantIds.map(merchantId => products.filter(product => product.merchantId === merchantId));
  })
});

const graphQLServer = new ApolloServer({
  schema: makeExecutableSchema({
    typeDefs: [typeDefs],
    resolvers
  }),
  context: ({req}) => ({
    currentUser: req.currentUser, // handled by middleware
    loaders: loaders()
  })
});

export default graphQLServer;