feat: add defaults to schemas (#120)

lib/goal.ex

@@ -459,7 +459,9 @@ defmodule Goal do
       Returns the validated parameters or an error changeset.
       """
       @spec validate(Ecto.Changeset.t()) :: {:ok, map()} | {:error, Ecto.Changeset.t()}
-      def validate(%Changeset{valid?: true, changes: changes}), do: {:ok, changes}
+      def validate(%Changeset{valid?: true} = changeset),
+        do: {:ok, Changeset.apply_changes(changeset)}
+
       def validate(%Changeset{valid?: false} = changeset), do: {:error, changeset}
 
       @doc """
@@ -660,7 +662,7 @@ defmodule Goal do
     |> build_changeset(params)
     |> Map.put(:action, :validate)
     |> case do
-      %Changeset{valid?: true, changes: changes} -> {:ok, changes}
+      %Changeset{valid?: true} = changes -> {:ok, Changeset.apply_changes(changes)}
       %Changeset{valid?: false} = changeset -> {:error, changeset}
     end
   end
@@ -680,8 +682,9 @@ defmodule Goal do
   @spec build_changeset(schema(), params()) :: Changeset.t()
   def build_changeset(schema, params) do
     types = get_types(schema)
+    defaults = build_defaults(schema)
 
-    {%{}, types}
+    {defaults, types}
     |> Changeset.cast(params, Map.keys(types), force_changes: true)
     |> validate_required_fields(schema)
     |> validate_basic_fields(schema)
@@ -793,6 +796,15 @@ defmodule Goal do
     end)
   end
 
+  defp build_defaults(schema) do
+    Enum.reduce(schema, %{}, fn {field, rules}, acc ->
+      case Keyword.get(rules, :default) do
+        nil -> acc
+        default -> Map.put_new(acc, field, default)
+      end
+    end)
+  end
+
   defp validate_required_fields(%Changeset{} = changeset, schema) do
     required_fields =
       Enum.reduce(schema, [], fn {field, rules}, acc ->

test/goal_test.exs

@@ -70,6 +70,11 @@ defmodule GoalTest do
     optional(:status, :enum, values: @statuses)
   end
 
+  defparams :defaults do
+    required(:status, :enum, values: @statuses, default: :pending)
+    optional(:name, :string, default: "The one who shall not be named")
+  end
+
   describe "__using__/1" do
     test "schema/0" do
       assert schema() == %{id: [type: :integer, required: true]}
@@ -292,6 +297,14 @@ defmodule GoalTest do
                   fields2: %{"hello" => "world"},
                   fields4: [%{"bye" => "world"}]
                 }}
+
+      assert validate(:defaults, %{}) == {
+               :ok,
+               %{status: :pending, name: "The one who shall not be named"}
+             }
+
+      assert validate(:defaults, %{status: :done, name: "Voldemort"}) ==
+               {:ok, %{status: :done, name: "Voldemort"}}
     end
   end
 
@@ -344,6 +357,12 @@ defmodule GoalTest do
 
       assert Goal.validate_params(schema, params, opts) == {:ok, %{}}
     end
+
+    test "includes default value when one is not provider" do
+      schema = %{name: [type: :string, default: "Harry Potter"]}
+
+      assert Goal.validate_params(schema, %{}) == {:ok, %{name: "Harry Potter"}}
+    end
   end
 
   describe "build_changeset/2" do
@@ -948,6 +967,19 @@ defmodule GoalTest do
       assert errors_on(changeset_4) == %{status: ["is invalid"]}
     end
 
+    test "default" do
+      schema = %{
+        status: [type: :enum, values: [:active, :inactive], default: :active, required: true],
+        name: [type: :string]
+      }
+
+      data_5 = %{}
+
+      changeset_5 = Goal.build_changeset(schema, data_5)
+
+      assert data_on(changeset_5) == %{status: :active}
+    end
+
     test "enum, string-based" do
       schema = %{status: [type: :enum, values: ["active", "inactive"]]}
 

test/test_helper.exs

@@ -10,6 +10,8 @@ defmodule Goal.Helpers do
       end)
     end)
   end
+
+  def data_on(%Ecto.Changeset{data: data}), do: data
 end
 
 defmodule Goal.DemoSchema do