How do these libraries compare to Ash? Can Ash load nested map data into structs to and from JSON?
user20230119
zachdaniel
Creator of Ash
Easily, yes. You can use the :embedded data layer to model an Ash.Resource that behaves like an Ash.Type.
defmodule MyApp.Profile do
use Ash.Resource, data_layer: :embedded
attributes do
attribute :bio, :string, allow_nil?: false
end
end
# on `User` for example
attribute :profile, MyApp.Profile
The above has various interesting benefits like the ability to leverage policies, validations, custom actions on the resource to handle updating logic etc.
For simple map → struct validation, you can use the :struct type with the :fields constraint. I typically recommend using Ash.Type.NewType for this, which creates a new type based off of another type and constraints. For example:
defmodule MyApp.Profile do
destruct [:bio]
use Ash.Type.NewType, subtype_of: :struct, constraints: [
instance_of: __MODULE__,
fields: [
bio: [type: :string, allow_nil?: false, constraints: [min_length: 25]]
]
]
end
You can use custom types as field types, etc, allowing for pretty much anything you could want to do.
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