Graphql datatypes

Documentation

type docs (scroll down)

https://graphql.org/learn/schema/

Primitives

String
Int
Float
Boolean
ID         # see docs

Enums

enum PrimaryColor {
  RED
  BLUE
  YELLOW
}

Lists

[String]   # homogenous typed list
[String!]  # list can be null, members must be strings (not null)

Interfaces

In your schema (note you can implement multiple interfaces)

# schema
interface Animal {
  species: String!
  age:     Int!
}

type Duck implements Animal {
  species: String!
  age:     Int!
  quack:   String!
}

You can return an Animal (which really returns any of the subtypes).
When referring to fields not part of the return type, you need to specify the object it belongs to.

{
  animal {
    species
    age
    ... on Duck {
      quack
    }
  }
}