README.md

Graphql Resolver Optimization

Purpose of this repository is to provide an example of resolvers optimization in GraphQL to avoid overfetching.

• Usage of "field resolvers" allowing resolvers to fetch only what is necessary
• Implementation of the facebook dataloder library to cope with the N+1 problem

Setup

$ yarn install
$ yarn dev

go to http://localhost:8080/graphql

Example 1

Run below query in playground:

query {
  user(id: 2) {
    id
    cars {
      id
      model
      registration_plate
    }
  }
}

This query should trigger only 1 API call:

/users/2/cars

Example 2

query {
  users {
    id
    firstName
    lastName
    cars {
      id
      model
      registration_plate
    }
  }
}

This query should trigger 2 API calls:

/users
/cars?ids[]=XXX&ids[]=YYY

Example 3

query {
  user(id: 1) {
    id
    firstName
    lastName
    cars {
      id
      model
      registration_plate
    }
  }
}

This query should trigger only 2 API calls:

/users?ids[]=1
/users/1/cars

You can find query examples in examples directory.