GraphQL UserConnection with totalCount

UserConnection.js

import { GraphQLInt, GraphQLNonNull, GraphQLInputObjectType } from "graphql";
import { connectionDefinitions, connectionArgs } from "graphql-relay";

import UserType from "./UserType";

// References
// http://graphql.org/learn/pagination/
// http://dev.apollodata.com/react/pagination.html
// https://www.reindex.io/blog/relay-graphql-pagination-with-mongodb/
// https://github.com/graphql/graphql-relay-js
// https://dev-blog.apollodata.com/understanding-pagination-rest-graphql-and-relay-b10f835549e7

// totalCount

// neither graphql-relay-js or relay-mongodb-connection expose totalCount
// https://github.com/mikberg/relay-mongodb-connection

// adriexnet has submitted a pull request to graphql-relay-js but the library seems a little dead
// https://github.com/adriexnet/relay-mongodb-connection/blob/develop/src/connectionFromMongoCursor.js

// graphql-relay-js can be manually overwritten throught the connectionFields
// https://stackoverflow.com/questions/34192507/how-to-pass-total-count-to-the-client-in-pageinfo

// pageInfo

// pageInfo.hasPreviousPage is always false if you are paging forwards
// https://github.com/graphql/graphql-relay-js/issues/58
// https://github.com/graphql/graphql-relay-js/issues/103

// relay-mongodb-connection uses it's own logic which can be modified here
// https://github.com/adriexnet/relay-mongodb-connection/blob/develop/src/utils.js#L39

export const {
	connectionType,
	edgeType
} = connectionDefinitions({
	nodeType: UserType,
	connectionFields: () => ({
		totalCount: {
			type: new GraphQLNonNull(GraphQLInt),
			resolve: connection => connection.totalCount,
// 			description: `A count of the total number of objects in this connection, ignoring pagination.
// This allows a client to fetch the first five objects by passing "5" as the
// argument to "first", then fetch the total count so it could display "5 of 83",
// for example.`
		}
	})
});

const Pagination = new GraphQLInputObjectType({
  name: 'Pagination',
  fields: connectionArgs
});

export const UserConnection = connectionType;
export const UserEdge = edgeType;
export const UserPagination = Pagination;

users.js

import { GraphQLString } from "graphql";

import { connectionArgs } from "graphql-relay";
import connectionFromMongoCursor from "relay-mongodb-connection";
import infoToProjection from "graphql-mongodb-projection";

import { User } from "../../models";

import { UserConnection, UserPagination } from "./UserConnection";

export const users = {
	type: UserConnection,
	args: {
		category: { type: GraphQLString },
		pagination: { type: UserPagination }
	},
	async resolve(root, { category, pagination }, ctx, info) {
		const { user } = ctx.state;

		const hasCategory = category ? { category } : {};
		const query = { ...hasCategory };
		const projection = infoToProjection(info);

		try {
			const usersList = await connectionFromMongoCursor(
				User.secureFind(user, query, projection),
				pagination
			);

			if (!usersList) throw "not found";

			const totalCount = await User.secureCount(user, query);

			const userListWithTotalCount = {
				...usersList,
				totalCount
			};

			return userListWithTotalCount;
		} catch (error) {
			throw error;
		}
	}
};

export default users;

usersQuery.graphql

query {
  users(pagination: {first: 3}) {
    totalCount
    
    edges {
      node {
        _id
      }
    }
  }
}

usersResponse.json

{
  "data": {
    "users": {
      "totalCount": 25,
      "edges": [
        {
          "node": {
            "_id": "58eba048307ce2316004bb2c"
          }
        },
        {
          "node": {
            "_id": "5922c481ade5f823f48d69af"
          }
        },
        {
          "node": {
            "_id": "5928372952ae8416ec532ef9"
          }
        }
      ]
    }
  }
}