A non-embedded union attribute change will be represented as a map:

%{ to: nil } %{ to: %{value: value, type: type } } %{ from: %{value: value, type: type }, to: %{value: value, type: type } } %{ unchanged: %{value: value, type: type } }

If the from & to are embedded resources with the same primary key then, we'll have consider it changed and represent it as:

%{ changed: %{type: type, updated: %{ ...attributes... } } }

If the union value is an embedded resource the value key will be replaced with created, unchanged, updated, destroyed.

%{ from: nil, created: %{type: type, value: %{ ...attributes... } } } %{ unchanged: %{type: type, value: %{ ...attributes... } } } %{ updated: %{type: type, value: %{ ...attributes... } } } %{ from: %{type: type, value: value}, created: %{type: type, value: %{ ...attributes... } } %{ destroyed: %{type: type, value: %{ ...attributes... } }, to: nil } %{ destroyed: %{type: type, value: %{ ...attributes... } }, created: %{type: type, value: %{ ...attributes... } } } %{ destroyed: %{type: type, destroyed: %{ ...attributes... } }, to: %{type: type, value: value } }