Implementing Interfaces and Union Types

GraphQL allows you to design highly flexible APIs. Sometimes, you need a field that can return different types of objects, or you want to define a shared set of fields that multiple types must implement. This is where polymorphism comes in.

We'll explore two key concepts for achieving this: Interfaces and Union Types.

Imagine you have different types of media, like a Book and a Movie. Both might have a title and a releaseYear. Instead of duplicating these fields, you can define an Interface.

An interface is a contract that specifies a set of fields that any type implementing it must include. It's like a blueprint for common functionality.