Configurable jason/transformer/flattenable in Nested

README.md

@@ -18,6 +18,7 @@ end
 I suggest adding [`boundary`](https://hexdocs.pm/boundary) as a dependency since that is used in this project.
 
 ## Changelog
+* `1.2.5` — `use Estructura.Nested flattenable: boolean(), jason: boolean(), transformer: boolean()`
 * `1.2.3` — Several `coerce/1` and `validate/1` clauses, default coercers
 * `1.2.2` — `Estructura.Flattenable`
 * `1.2.1` — Generators for `:datetime` and `:date`

lib/estructura/nested.ex

@@ -400,11 +400,26 @@ defmodule Estructura.Nested do
     struct = struct_ast(fields)
     generator = generator_ast(fields)
 
+    need_jason? =
+      nested? or
+        (Module.open?(module) and
+           module |> Module.get_attribute(:__estructura_nested__) |> Map.get(:jason, true))
+
+    need_transformer? =
+      nested? or
+        (Module.open?(module) and
+           module |> Module.get_attribute(:__estructura_nested__) |> Map.get(:transformer, true))
+
+    need_flattenable? =
+      nested? or
+        (Module.open?(module) and
+           module |> Module.get_attribute(:__estructura_nested__) |> Map.get(:flattenable, true))
+
     [
       quote do
         if unquote(nested?), do: @moduledoc(false)
 
-        if {:module, Jason} == Code.ensure_compiled(Jason) do
+        if unquote(need_jason?) and {:module, Jason} == Code.ensure_compiled(Jason) do
           @derive Jason.Encoder
 
           @doc "Safely parses the json, applying all the specified validations and coercions"
@@ -420,8 +435,8 @@ defmodule Estructura.Nested do
             do: input |> Jason.decode!() |> unquote(module).cast!()
         end
 
-        @derive Estructura.Transformer
-        @derive Estructura.Flattenable
+        if unquote(need_transformer?), do: @derive(Estructura.Transformer)
+        if unquote(need_flattenable?), do: @derive(Estructura.Flattenable)
 
         defstruct unquote(Macro.escape(struct))
 

mix.exs

@@ -2,7 +2,7 @@ defmodule Estructura.MixProject do
   use Mix.Project
 
   @app :estructura
-  @version "1.2.4"
+  @version "1.2.5"
 
   def project do
     [

test/support/structs.ex

@@ -135,7 +135,7 @@ defmodule Estructura.User do
 
   """
 
-  use Estructura.Nested
+  use Estructura.Nested, jason: true
 
   shape(%{
     created_at: :datetime,