relay-mongodb-connection

Like connectionFromArray() but for MongoDB cursors

Install

1npm install --save relay-mongodb-connection

Usage

Give it a cursor from mongodb, and it handles pagination int he same way graphql-relay does for arrays.

1import connectionFromMongoCursor from 'relay-mongodb-connection';

Also supports mongoose's querys and aggregations.

1import { connectionFromMongooseQuery } from 'relay-mongodb-connection';
2import { connectionFromMongooseAggregate } from 'relay-mongodb-connection';

At a glance

Pass it a MongoDB cursor and connectionArgs, and it's happy.

1resolve(obj, { ...args }) {
2  return connectionFromMongoCursor(
3    db.collection('users').find({}),
4    args
5  );
6}

Optionally give it a mapper function:

1resolve(obj, { ...args }) {
2  return connectionFromMongoCursor(
3    db.collection('users').find({}),
4    args,
5    (user) => Object.assign(user, { id: user._id })
6  );
7}

And for Mongoose users:

1resolve(obj, { ...args }) {
2  return connectionFromMongooseQuery(
3    User.find({}),  // User.aggregate() also works
4    args,
5    (user) => Object.assign(user, { id: user._id })
6  );
7}

Example

1// ...
2import connectionFromMongoCursor from 'relay-mongodb-connection';
3// ...
4
5// Instead of resolving, synchronously returns a MongoDB Cursor.
6function getSpaceshipsForUser(userId) {
7  return db.collection('spaceships').find({
8    user: new ObjectId(userId)
9  });
10}
11
12export const GraphQLUser = new GraphQLObjectType({
13  name: 'User',
14  fields: {
15    id: globalIdField('User'),
16    spaceships: {
17      type: SpaceshipConnection,
18      args: {
19        ...connectionArgs,
20      },
21      resolve(user, { ...args }) {
22        const spaceshipCursor = getSpaceshipsForUser(user._id);
23        return connectionFromMongoCursor(spaceshipCursor, args);
24      }
25    }
26  }
27});

connectionFromMongoCursor automatically skips and limits the MongoDB Cursor so that only the necessary documents are retrieved from the database.

Changelog

See CHANGELOG.md

Testing

1MONGO_URL=mongodb://192.168.99.100/mongodbconnection npm test

License

MIT © Mikael Berg