zachdaniel:

Hey all, I’ve added a relatively experimental new type to ash core called :union (or Ash.Type.Union ). Its in main currently. Some work will be done in the future to support rendering this automatically in ash_graphql (but not for input types, there are no union input types in ash_graphql so you’ll have to write your own input types there or just use :json or something for now). Its not as nice/easy as something like a typescript union, because this we are actually retaining the fact that this is a union type. Additionally, you won’t be able to filter on unions as intuitively as you like because unions will be :map (json) under the hood. Still, it could be useful for others and the ergonomics of it can be improved. Here is an example usage:

# using `tag` and `tag_value` to union maps (or embedded resources
attribute :metadata, :union do
  constraints types: [
    foo: [
      type: MyApp.Foo,
      tag: :type,
      tag_value: :foo
    ],
     bar: [
      type: MyApp.Bar,
      tag: :type,
      tag_value: :bar
    ]
  ]
end

# using type casting (we try to cast it as each type in the list) for literals
attribute :width, :union do
  constraints types: [
    int: [
      type: :integer
      constraints: [
        max: 10
      ]
    ],
    string: [
      type: :string,
      constraints: [
        match: ~r/regex/
      ]
    ]
  ]
end

Anyone using main is free to give it a try and let me know what you think 🙂

jharton:

Thanks for this <@197905764424089601> this is awesome. I’ll give it a whirl soon enough

zachdaniel:

The union type has shipped in 2.6.4 and graphql support for union types is in main