GraphQL Cheat Sheet

Query

Make a query:

{
    Photo {
        name
        url
    }
}

Send to GraphQL endpoint with cURL:

curl  'http://someurl.com/'
  -H 'Content-Type: application/json'
  --data '{"query":"{ Photo {name url}}"}'

Mutation

Modify data:

mutation {
  setLiftStatus(id: "panorama" status: OPEN) {
    name
    status
  }
}

Send to GraphQL endpoint with cURL:

curl 'http://someurl.com/'
  -H 'Content-Type: application/json'
  --data '{"query":"mutation {setLiftStatus(id: \"panorama\" status: OPEN) {name status}}"}'

Define Types

A type represents a custom object and these objects describe your application’s core features.
A scalar type is not an object type. It does not have fields.
An enum is a scalar type that allow a field to return a restrictive set of string values.

scalar DateTime

type Photo {
    id: ID!
    name: String!
    url: String!
    description: String
    created: DateTime!
    category: PhotoCategory!
}

enum PhotoCategory {
    SELFIE
    PORTRAIT
    ACTION
    LANDSCAPE
    GRAPHIC
}

Connections and Lists

One to many connection example:

type User {
    githubLogin: ID!
    name: String
    avatar: String
    postedPhotos: [Photo!]!
}

Many to many connection example:

type User {
    ...
    inPhotos: [Photo!]!
}

type Photo {
    ...
    taggedUsers: [User!]!
}

Union type example:

union AgendaItem = StudyGroup | Workout

type StudyGroup {
    name: String!
    subject: String
    students: [User!]!
}

type Workout {
    name: String!
    reps: Int!
}

type Query {
    agenda: [AgendaItem!]!
}

Arguments

type Query {
    Photo(id: ID!): Photo! # pass ID to select photo
    allPhotos(category: PhotoCategory): [Photo!]! # pass category to filter photos
}

Paging

type Query {
    allPhotos(first: Int=25 where: Int=0): [Photo!]! # cursor-based
    allPhotos(first: Int=25 after: Int=0): [Photo!]! # Relay-style
    allPhotos(limit: Int=25 offset: Int=0): [Photo!]! # offset-based
}

Sorting

enum SortablePhotoField {
    name
    description
    category
    created
}

Query {
    allPhotos(
        sortBy: SortablePhotoField = created
    ): [Photo!]!
}

query {
    allPhotos(sortBy: name)
}

Variable

Variables replace the static value in the query so that we can pass dynamic values

mutation createSong($title:String! $numberOne:Int $by:String!) {
  addSong(title:$title, numberOne:$numberOne, performerName:$by) {
    id
    title
    numberOne
  }
}

# use variable name as the JSON keys
{
  "title": "No Scrubs",
  "numberOne": true,
  "by": "TLC"
}

Alias

Change the field names in the response object within the query.

query liftsAndTrails {
  open: liftCount(status: OPEN)
  chairlifts: allLifts {
    liftName: name
    status
  }
  skiSlopes: allTrails {
    name
    difficulty
  }
}

Fragment

Fragments are selection sets that can be reused in multiple operations.

fragment liftInfo on Lift {
  name
  status
  capacity
  night
  elevationGain
}

query {
    Lift(id: "jazz-cat") {
      ...liftInfo
      trailAccess {
        name
        difficulty
      }
    }
    Trail(id: "river-run") {
      name
      difficulty
      accessedByLifts {
        ...liftInfo
      }
    }
}

Reference

Eve Porcello and Alex Banks. 2018. Learning GraphQL: Declarative Data Fetching for Modern Web Apps (1st. ed.). O’Reilly Media, Inc.