3.2 KiB
| title | updated | category |
|---|---|---|
| GraphQL | 2019-07-07 | API |
Intro
Queries
{: .-three-column}
Basic query
{ status }
↓
{ status: 'available' }
{: .-setup}
Nesting
{ hero { name height } }
↓
{ hero:
{ name: "Luke Skywalker",
height: 1.74 } }
{: .-setup}
Lists
{ friends { name } }
↓
{ friends:
[ { name: "Luke Skywalker" },
{ name: "Han Solo" },
{ name: "R2D2" } ] }
{: .-setup}
GraphQL queries look the same for both single items or lists of items.
Lookups
{
hero(id: "1000") { id name }
}
↓
{ hero:
{ id: "1000",
{ name: "Luke Skywalker" } }
{: .-setup}
Aliases
{
luke: hero(id: "1000") { name }
han: hero(id: "1001") { name }
}
↓
{ luke:
{ name: "Luke Skywalker" },
han:
{ name: "Han Solo" } }
{: .-setup}
Operation names and variables
Query
query FindHero($id: String!) {
hero(id: $id) { name }
}
Just to make things less ambiguous. Also, to use variables, you need an operation name.
Variables
{ id: '1000' }
Mutations
Query
{ createReview($review) { id } }
Variables
{ review: { stars: 5 } }
↓
{ createReview: { id: 5291 } }
Mutations are just fields that do something when queried.
Multiple types
{
search(q: "john") {
id
... on User { name }
... on Comment { body author { name } }
}
}
Great for searching.
Over HTTP
GET
fetch('http://myapi/graphql?query={ me { name } }')
POST
fetch('http://myapi/graphql', {
body: JSON.stringify({
query: '...',
operationName: '...',
variables: { ... }
})
})
Schema
{: .-three-column}
Basic schemas
type Query {
me: User
users(limit: Int): [User]
}
type User {
id: ID!
name: String
}
See: sogko/graphql-shorthand-notation-cheat-sheet
Built in types
Scalar types
| Int | Integer |
| Float | Float |
| String | String |
| Boolean | Boolean |
| ID | ID |
Type definitions
| scalar | Scalar type |
| type | Object type |
| interface | Interface type |
| union | Union type |
| enum | Enumerable type |
| input | Input object type |
Type modifiers
| String | Nullable string |
| String! | Required string |
| [String] | List of strings |
| [String]! | Required list of strings |
| [String!]! | Required list of required strings |
Mutations
type Mutation {
users(params: ListUsersInput): [User]!
}
Interfaces
interface Entity {
id: ID!
}
type User implements Entity {
id: ID!
name: String
}
Enums
enum DIRECTION {
LEFT
RIGHT
}
type Root {
direction: DIRECTION!
}
{: data-line="1,2,3,4"}
Unions
type Artist { ··· }
type Album { ··· }
union Result = Artist | Album
type Query {
search(q: String): [Result]
}
{: data-line="4"}