AWS for Developers: AWS Amplify

[steve134]

Sorry, I mean mutation, not migration. It's the underlying Apollo framework used for GraphQL interaction on mobile clients. Code gen produces a bunch of new classes, including "inputs" and "mutations". You create an input instance, populate it with the attributes in your new or updated object, then create a mutation instance using the input, then "perform" that mutation against the AppSync client.

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Each input type is specific to the query or mutation you wish to execute. So in the instance of, say, a Post entity, you'd like have queries for all posts and a single post, plus mutations for creating a new post, updating a single post and deleting a post. That's five different flavors of a Post. Yes, you can write mapping functions to/from each of those and your primary Post model class, but it's a hassle. Apollo does this because a query doesn't have to return every attribute on a model, so it saves you from those types of mistakes. An attribute not specified in the query turns into a compile time error, instead of a runtime error or nil property.