Extract collection to Collectible module (#34)

* Extract collection to Collectible module
* Use nested module blocks instead of compact form
* Use yield instead of block.call
* Tell Rubocop to ignore nested method definition (But just here)
* Add frozen string literal comment to new class

lib/nacre/concerns/collectible.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+module Nacre
+  module Collectible
+    def self.included(base)
+      base.class_exec do
+        def initialize(resource_list = []) # rubocop:disable NestedMethodDefinition
+          @members = []
+
+          resource_list.each do |resource_params|
+            members << self.class.resource_class.new(resource_params)
+          end
+        end
+      end
+    end
+
+    def members
+      @members
+    end
+
+    def members=(list)
+      @members = list
+    end
+
+    def each
+      members.each do |member|
+        yield member
+      end
+    end
+
+    def params
+      members.map(&:params)
+    end
+  end
+end

lib/nacre/order/invoice_collection.rb

@@ -1,26 +1,12 @@
+require 'nacre/concerns/collectible'
+
 module Nacre
   class Order::InvoiceCollection
-
+    include Collectible
     include Enumerable
 
-    attr_accessor :members
-
-    def initialize(resource_list = [])
-      self.members = []
-      resource_list.each do |resource_params|
-        members << Nacre::Order::Invoice.new(resource_params)
-      end
-    end
-
-    def each(&block)
-      members.each do |member|
-        block.call(member)
-      end
-    end
-
-    def params
-      members.map(&:params)
+    def self.resource_class
+      Nacre::Order::Invoice
     end
-
   end
 end

lib/nacre/product/sales_channel_collection.rb

@@ -1,26 +1,14 @@
+require "nacre/concerns/collectible"
+
 module Nacre
   class Product::SalesChannelCollection
 
+    include Collectible
     include Enumerable
     extend Inflectible
 
-    attr_accessor :members
-
-    def initialize(resource_list = [])
-      self.members = []
-      resource_list.each do |resource_params|
-        members << Nacre::Product::SalesChannel.new(resource_params)
-      end
-    end
-
-    def each(&block)
-      members.each do |member|
-        block.call(member)
-      end
-    end
-
-    def params
-      members.map(&:params)
+    def self.resource_class
+      Nacre::Product::SalesChannel
     end
 
     def product_name
@@ -34,6 +22,5 @@ def product_name
         name_sources.first.product_name
       end
     end
-
   end
 end