Sample schema for "Implementing GraphQL server" article

findFlights_schema_01.js

// @flow

import {
  GraphQLObjectType,
  GraphQLList,
  GraphQLString,
  GraphQLInt,
  GraphQLNonNull,
  GraphQLSchema,
} from 'graphql';
import fetch from 'node-fetch';
import { DateTime } from 'luxon';
import { globalIdField } from 'graphql-relay';
import { GraphQLDate } from 'graphql-iso-date';

type PriceData = {
  amount: number,
  currency: string,
};

type FlightData = {
  id: string,
  destination: string,
  price?: PriceData,
};

const sanitizeFlight = (flight: Object, currency: string): FlightData => ({
  id: flight.id,
  destination: flight.cityTo,
  price: {
    amount: flight.price,
    currency,
  },
});

const getFlights = async (departureDate: Date) => {
  const date = DateTime.fromJSDate(departureDate, { zone: 'utc' });
  const departure = date.toFormat('dd/MM/yyyy');
  const url = `https://api.skypicker.com/flights?flyFrom=Prague&dateFrom=${departure}&dateTo=${departure}`;
  const response = await fetch(url, { method: 'GET' });

  if (response.status >= 300) {
    throw new Error(response.statusText);
  }

  const payload = await response.json();

  if (payload && Array.isArray(payload.data)) {
    return payload.data.map(flight => sanitizeFlight(flight, payload.currency));
  }

  throw new Error('No data!');
};

const Price = new GraphQLObjectType({
  name: 'Price',
  fields: {
    amount: {
      type: GraphQLInt,
    },
    currency: {
      type: GraphQLString,
    },
  },
});

const Flight = new GraphQLObjectType({
  name: 'Flight',
  fields: {
    id: globalIdField(),
    destination: {
      type: GraphQLString,
      description: 'Name of the destination city.',
      resolve: ({ destination }: FlightData) => destination,
    },
    price: {
      type: Price,
      resolve: ({ price }: FlightData) => price,
    },
  },
});

const RootQuery = new GraphQLObjectType({
  name: 'RootQuery',
  fields: {
    findFlights: {
      type: new GraphQLList(Flight),
      description: 'Search for some cheap flights on specific date.',
      args: {
        departureDate: {
          type: new GraphQLNonNull(GraphQLDate),
        },
      },
      resolve: (_, { departureDate }): Promise<FlightData[]> => getFlights(departureDate),
    },
  },
});

const schema = new GraphQLSchema({
  query: RootQuery,
});

export default schema;