GraphQL Batch

This library is an alternative to batching with dataloader that works with both graphql and graphql-tools.

Note: this is a fork of graphql-resolve-batch, except we give users finer-grained control of their batching.

import { GraphQLObjectType, GraphQLString } from 'graphql'
import createBatchResolver from 'graphql-batch'

const UserType = new GraphQLObjectType({
  // ...
});

const QueryType = new GraphQLObjectType({
  name: 'Query',
  fields: {
    user: {
      type: UserType,
      resolve: createBatchResolver(async (sources, args, [context]) => {
        const { db } = context
        const users = await db.loadUsersByIds(sources.map(({ id }) => id))
        return users
      })
    }
  }
})

Usage

Install graphql-batch with

$ npm install --save graphql-batch graphql

or

$ yarn add graphql-batch graphql

and import it as

import createBatchResolver from 'graphql-batch';

Examples

1. This example batches up requests to node into a single request to nodes

const resolve = createBatchResolver(
  (roots, argss, [context], [info]) =>  
    queries['nodes']({}, { ids: argss.map(args => args && args.id) }, context, info),
  // batch by request id and root field name
  (parent, args, context, info) =>
    `${context.req && context.req.id}${info.fieldNodes[0].name.value}`)
)

return {
  Query: {
    node: {
      resolve
    }
  }
}

Note: the second parameter is optional and will default to use the first fieldName as the key:

function defaultCompositeKey(parent, args, context, info) {
  return info.fieldNodes[0].name.value
}

Credits

• This is a fork of graphql-resolve-batch by @calebmer