Notes about GraphQL

GraphQL basics

  • GraphQL

    • describe your data
    • ask for what you want
    • get predictable results

  • A GraphQL service defines types and fields on those types. A function is created for each field on each type.

    • field can be a specific type (like String) or an Object

    • arguments can be passed to fields when making a query

      {
  human(id: "1000") {
    name
    height
  }
}

  • GraphQL schema and types

    type Character {
  name: String!
  appearsIn: [Episode]!
}
    • GraphQL Object type Character
    • fields name and appearsIn
    • Scalar type String
    • ! non-nullable (will always return a value when queried)
    • array [Episode]

  • Arguments

    • every field can have 0 or more arguments
    • all arguments are named
    • all arguments are passed by name specifically (unlike JS or Python where functions take a list of ordered arguments
    • required or optional

  • Scalar types

    • fields that resolve to real data
    • leaves of the query
    • default scalar types:
      • Int
      • Float
      • String
      • Boolean
      • ID unique identifier
    • custom scalar types are possible i.e. Date
    • Enums

  • Modifiers: Non-Null and List (array)

    • List [] can be null
    • a member of the list can not be null or it will generate an error
    • []! the actual list can not be null though a member can be null

  • Introspection is a beautiful thing; ask for __schema for all the good stuff on the types

GraphQL Client needs

  • Pagination
    • plurals
    • slicing
    • pagination and edges
    • Connections
  • Caching
    • ID
    • pros and cons of globally unique IDs
    • server defined or client derived are both options