New configuration: Importmap

This should allow configuring importmaps. This commit is a bit larger,
but it allows setting default configurations to lambdas, so we can have
access to e.g. `Alchemy::Engine`.

Author: mamhoff

lib/alchemy/configuration.rb

@@ -9,6 +9,7 @@
 require "alchemy/configuration/class_option"
 require "alchemy/configuration/class_set_option"
 require "alchemy/configuration/integer_option"
+require "alchemy/configuration/pathname_option"
 require "alchemy/configuration/regexp_option"
 require "alchemy/configuration/string_option"
 

lib/alchemy/configuration/base_option.rb

@@ -9,13 +9,21 @@ def self.value_class
 
       def initialize(value:, name:, **args)
         @name = name
-        validate(value) unless value.nil?
+        validate(value) unless value.nil? || value.is_a?(Proc)
         @value = value
       end
-      attr_reader :name, :value
+      attr_reader :name
 
-      def validate(value)
-        raise ConfigurationError.new(name, value, self.class.value_class.name) unless value.is_a?(self.class.value_class)
+      def value
+        return @value unless @value.is_a?(Proc)
+
+        evaluated_value = @value.call
+        validate(evaluated_value)
+        evaluated_value
+      end
+
+      def validate(validatable_value)
+        raise ConfigurationError.new(name, validatable_value, self.class.value_class.name) unless validatable_value.is_a?(self.class.value_class)
       end
     end
   end

lib/alchemy/configuration/collection_option.rb

@@ -16,10 +16,17 @@ def initialize(value:, name:, item_type:, collection_class: Array, **args)
         @collection_class = collection_class
         @item_option_class = "Alchemy::Configuration::#{item_type.to_s.classify}Option".constantize
         super
-        @value = value.map { @item_option_class.new(value: _1, name: "#{name}_item") }
+        if value.is_a?(Proc)
+          @value = value
+        else
+          @value = value.map { @item_option_class.new(value: _1, name: "#{name}_item") }
+        end
       end
 
       def value
+        return @collection_class.new(@value.map(&:value)) unless @value.is_a?(Proc)
+        evaluated_value = @value.call
+        @value = evaluated_value.map { @item_option_class.new(value: _1, name: "#{name}_item") }
         @collection_class.new(@value.map(&:value))
       end
 

lib/alchemy/configuration/pathname_option.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module Alchemy
+  class Configuration
+    class PathNameOption < BaseOption
+      def self.value_class
+        ::Pathname
+      end
+    end
+  end
+end

lib/alchemy/configurations/importmap.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+module Alchemy
+  module Configurations
+    class Importmap < Alchemy::Configuration
+      option :importmap_path, :path_name, default: ->() { Alchemy::Engine.root.join("config/importmap.rb") }
+      option :source_paths, :collection, collection_type: Array, item_type: :path_name, default: -> do
+        [
+          Alchemy::Engine.root.join("app/javascript"),
+          Alchemy::Engine.root.join("vendor/javascript")
+        ]
+      end
+      option :name, :string, default: "alchemy_admin"
+    end
+  end
+end

lib/alchemy/configurations/main.rb

@@ -4,6 +4,7 @@
 require "alchemy/configurations/default_language"
 require "alchemy/configurations/default_site"
 require "alchemy/configurations/format_matchers"
+require "alchemy/configurations/importmap"
 require "alchemy/configurations/mailer"
 require "alchemy/configurations/preview"
 require "alchemy/configurations/sitemap"

spec/libraries/alchemy/configurations/importmap_spec.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe Alchemy::Configurations::Importmap do
+  let(:configuration) { described_class.new }
+
+  describe "default values" do
+    describe "#importmap_path" do
+      subject { configuration.importmap_path }
+      it { is_expected.to eq(Alchemy::Engine.root.join("config/importmap.rb")) }
+    end
+
+    describe "#source_paths" do
+      subject { configuration.source_paths }
+      it {
+        is_expected.to eq(
+          [
+            Alchemy::Engine.root.join("app/javascript"),
+            Alchemy::Engine.root.join("vendor/javascript")
+          ]
+        )
+      }
+    end
+
+    describe "#name" do
+      subject { configuration.name }
+      it { is_expected.to eq("alchemy_admin") }
+    end
+  end
+end