relay.md

graphql-sequelize and Relay

node lookups

relay will perform certain queries on a root "node" type. graphql-sequelize will automatically map these node lookups to findById calls.

If you wish to use non-sequelize entities, or if you want to override the default behaviour for sequelize models, you can specify a resolve function.

import {relay: {sequelizeNodeInterface}} from 'graphql-sequelize';
import sequelize from './your-sequelize-instance';

const {
  User
} = sequelize;

const {
  nodeInterface,
  nodeField,
  nodeTypeMapper
} = sequelizeNodeInterface(sequelize);

const userType = new GraphQLObjectType({
  name: User.name,
  fields: {
    id: globalIdField(User.name),
    name: {
      type: GraphQLString
    }
  },
  interfaces: [nodeInterface]
});

nodeTypeMapper.mapTypes({
  [User.name]: userType,

  //Non-sequelize models can be added as well
  SomeOther: {
    type: SomeOtherType, //Specify graphql type to map to
    resolve(globalId, context) { //Specify function to get entity from id
      const { id } = fromGlobalId(globalId);
      return getSomeOther(id);
    }
  }
});

const schema = new GraphQLSchema({
  query: new GraphQLObjectType({
    name: 'RootType',
    fields: {
      user: {
        type: userType,
        args: {
          id: {
            type: new GraphQLNonNull(GraphQLInt)
          }
        },
        resolve: resolver(User)
      },
      node: nodeField
    }
  })
});

If you make sure to call nodeTypeMapper.mapTypes with all your graphql types matching your sequelize models all node with global id lookups will work. You can also add any non-model mapping you'd like to `mapTypes'.

connections

graphql-sequelize's sequelizeConnection will automatically handle pagination via cursors, first, last, before, after and orderBy.

import {relay: {sequelizeConnection}} from 'graphql-sequelize';
import sequelize from './your-sequelize-instance';

const {
  User,
  Task
} = sequelize;


const taskType = new GraphQLObjectType({
  name: Task.name,
  fields: {
    id: globalIdField(Task.name),
    title: {
      type: GraphQLString
    }
  }
});

const userTaskConnection = sequelizeConnection({
  name: 'userTask',
  nodeType: taskType,
  target: User.Tasks | User // Can be an association for parent related connections or a model for "anonymous" connections
  // if no orderBy is specified the model primary key will be used.
  orderBy: new GraphQLEnumType({
    name: 'UserTaskOrderBy',
    values: {
      AGE: {value: ['createdAt', 'DESC']}, // The first ENUM value will be the default order. The direction will be used for `first`, will automatically be inversed for `last` lookups.
      TITLE: {value:  ['title', 'ASC']},
      CUSTOM: {value:  [function (source, args, context, info) {}, 'ASC']} // build and return custom order for sequelize orderBy option
    }
  }),
  where: function (key, value) {
    // for custom args other than connectionArgs return a sequelize where parameter

    return {[key]: value};
  },
  connectionFields: {
    total: {
      type: GraphQLInt,
      resolve: ({source}) => {
        /*
         * We return a object containing the source, edges and more as the connection result
         * You there for need to extract source from the usual source argument
         */
        return source.countTasks();
      }
    }
  },
  edgeFields: {
    wasCreatedByUser: {
      type: GraphQLBoolean,
      resolve: (edge) => {
        /*
         * We attach the connection source to edges
         */
        return edge.node.createdBy === edge.source.id;
      }
    }
  }
});

const userType = new GraphQLObjectType({
  name: User.name,
  fields: {
    id: globalIdField(User.name),
    name: {
      type: GraphQLString
    },
    tasks: {
      type: userTaskConnection.connectionType,
      args: userTaskConnection.connectionArgs,
      resolve: userTaskConnection.resolve
    }
  }
});

{
  user(id: 123) {
    tasks(first: 10, orderBy: AGE) {
      ...totalCount
      edges {
        ...getCreated
        cursor
        node {
          id
          title
        }
      }
    }
  }
}

fragment totalCount on userTaskConnection {
   total
}

fragment getCreated on userTaskEdge {
  wasCreatedByUser
}

You can pass custom args in your connection definition and they will automaticly be turned into where arguments. These can be further modified using the where option in sequelizeConnection.

const userTaskConnection = sequelizeConnection({
  name: 'userTask',
  nodeType: taskType,
  target: User.Tasks,
  where: function (key, value) {
    if (key === 'titleStartsWith') {
      return { title: { $like: `${value}%` } };
    } else {
      return {[key]: value};
    }
  },
});
const userType = new GraphQLObjectType({
  name: User.name,
  fields: {
    id: globalIdField(User.name),
    name: {
      type: GraphQLString
    },
    tasks: {
      type: userTaskConnection.connectionType,
      args: {
        ...userTaskConnection.connectionArgs, // <-- Load the defaults
        titleStartsWith: { // <-- Extend further yourself
          type: GraphQLString,
        }
      },
      resolve: userTaskConnection.resolve
    }
  }
});