Definisi Schema

Root Schema

schema {
  query: Query
  mutation: Mutation
}

Object Type

type User {
  id: ID!
  name: String!
  email: String
}

Query

Query Dasar

query {
  user(id: "1") {
    name
    email
  }
}

Query Bernama dengan Alias

query GetUsers {
  admin: user(role: ADMIN) { name }
  guest: user(role: GUEST) { name }
}

Mutation

Mutation Dasar

mutation {
  createUser(input: { name: "Alice" }) {
    id
    name
  }
}

Tipe Input

input CreateUserInput {
  name: String!
  email: String
}

Subscription

Subscription Dasar

subscription {
  messageAdded(channel: "general") {
    text
    sender { name }
  }
}

Ringkasan

subscription	Data real-time via WebSocket
Server push	Server mengirim pembaruan ke client
Single field	Hanya satu root field per subscription

Tipe

Scalar Type

Int	Integer 32-bit bertanda
Float	Bilangan pecahan presisi ganda
String	Urutan karakter UTF-8
Boolean	true atau false
ID	Identifier unik (diserialisasi sebagai String)

Modifier Tipe

String	String nullable
String!	String non-null
[String]	List nullable berisi string nullable
[String!]!	List non-null berisi string non-null

Enum & Union

enum Role { ADMIN USER GUEST }
union SearchResult = User | Post
interface Node { id: ID! }

Argumen & Variabel

Variabel

query GetUser($id: ID!) {
  user(id: $id) {
    name
  }
}
# Variables: { "id": "123" }

Nilai Default

query GetUsers($limit: Int = 10) {
  users(limit: $limit) { name }
}

Fragment

Fragment Bernama

fragment UserFields on User {
  id
  name
  email
}

Menggunakan Fragment

query {
  user(id: "1") { ...UserFields }
  admin: user(id: "2") { ...UserFields }
}

Inline Fragment

query {
  search(text: "a") {
    ... on User { name }
    ... on Post { title }
  }
}

Directive

Directive Bawaan

@include(if: Boolean!)	Sertakan field hanya jika kondisi benar
@skip(if: Boolean!)	Lewati field jika kondisi benar
@deprecated(reason: String)	Tandai field sebagai deprecated

Contoh Penggunaan

query GetUser($withEmail: Boolean!) {
  user(id: "1") {
    name
    email @include(if: $withEmail)
  }
}

Introspection

Introspection Tipe

query {
  __type(name: "User") {
    name
    fields { name type { name } }
  }
}

Introspection Schema

query {
  __schema {
    types { name kind }
    queryType { name }
  }
}

Field Introspection

__schema	Query tipe dan directive dari schema
__type(name:)	Query tipe tertentu berdasarkan nama
__typename	Mengembalikan nama tipe dari objek mana pun

Pola Umum

Pagination (gaya Relay)

query {
  users(first: 10, after: "cursor") {
    edges { node { name } cursor }
    pageInfo { hasNextPage }
  }
}

Penanganan Error

{
  "data": { "user": null },
  "errors": [{ "message": "Not found",
    "path": ["user"] }]
}

Praktik Terbaik

Beri nama operasi	Selalu beri nama query dan mutation
Gunakan variabel	Jangan interpolasi nilai langsung ke query
Minta field yang dibutuhkan	Hindari over-fetching dengan seleksi yang tepat
Gunakan fragment	Bagikan kumpulan field antar query

REFERENSI CEPAT GRAPHQL