added Helpers to dry up some logic for madeintandem#4

Author: Michael Crismali

lib/jsonb_accessor.rb

@@ -4,6 +4,7 @@
 
 require "jsonb_accessor/version"
 require "jsonb_accessor/fields_map"
+require "jsonb_accessor/helpers"
 require "jsonb_accessor/type_helper"
 require "jsonb_accessor/nested_base"
 require "jsonb_accessor/class_builder"
@@ -16,4 +17,5 @@ module JsonbAccessor
 
 ActiveSupport.on_load(:active_record) do
   ActiveRecord::Base.send(:include, JsonbAccessor)
+  ActiveRecord::Base.send(:include, JsonbAccessor::Helpers)
 end

lib/jsonb_accessor/class_builder.rb

@@ -37,19 +37,8 @@ def generate_class(namespace, new_class_name, attribute_definitions)
 
             define_method("#{attribute_name}=") do |value|
               instance_class = nested_classes[attribute_name]
+              instance = cast_nested_field_value(value, instance_class, __method__)
 
-              case value
-              when instance_class
-                instance = instance_class.new(value.attributes)
-              when Hash
-                instance = instance_class.new(value)
-              when nil
-                instance = instance_class.new
-              else
-                raise UnknownValue, "unable to set value '#{value}' is not a hash, `nil`, or an instance of #{instance_class} in #{__method__}"
-              end
-
-              instance.parent = self
               instance_variable_set("@#{attribute_name}", instance)
               attributes[attribute_name] = instance.attributes
               update_parent

lib/jsonb_accessor/helpers.rb

@@ -0,0 +1,19 @@
+module JsonbAccessor
+  module Helpers
+    def cast_nested_field_value(value, klass, method_name)
+      case value
+      when klass
+        instance = klass.new(value.attributes)
+      when Hash
+        instance = klass.new(value)
+      when nil
+        instance = klass.new
+      else
+        raise UnknownValue, "unable to set value '#{value}' is not a hash, `nil`, or an instance of #{klass} in #{method_name}"
+      end
+
+      instance.parent = self
+      instance
+    end
+  end
+end

lib/jsonb_accessor/macro.rb

@@ -78,19 +78,8 @@ def jsonb_accessor(jsonb_attribute, *value_fields, **typed_fields)
           jsonb_accessor_methods.instance_eval do
             define_method("#{field}=") do |value|
               instance_class = nested_classes[field]
+              instance = cast_nested_field_value(value, instance_class, __method__)
 
-              case value
-              when instance_class
-                instance = instance_class.new(value.attributes)
-              when Hash
-                instance = instance_class.new(value)
-              when nil
-                instance = instance_class.new
-              else
-                raise UnknownValue, "unable to set value '#{value}' is not a hash, `nil`, or an instance of #{instance_class} in #{__method__}"
-              end
-
-              instance.parent = self
               new_jsonb_value = (send(jsonb_attribute) || {}).merge(field.to_s => instance.attributes)
               write_attribute(jsonb_attribute, new_jsonb_value)
               super(instance)

lib/jsonb_accessor/nested_base.rb

@@ -1,5 +1,7 @@
 module JsonbAccessor
   class NestedBase
+    include Helpers
+
     attr_accessor :attributes, :parent
     alias_method :to_h, :attributes
 

spec/lib/helpers_spec.rb

@@ -0,0 +1,59 @@
+require "spec_helper"
+
+RSpec.describe JsonbAccessor::Helpers do
+  let(:dummy_class) do
+    Class.new do
+      attr_accessor :attributes, :parent
+
+      def initialize(attributes = {})
+        self.attributes = attributes
+      end
+    end
+  end
+  subject { Object.new.extend(JsonbAccessor::Helpers) }
+
+  describe "#cast_nested_field_value" do
+    it "assigns itself as the new object's parent" do
+      result = subject.cast_nested_field_value(nil, dummy_class, :foo)
+      expect(result.parent).to eq(subject)
+    end
+
+    context "value is the given class" do
+      let(:value) { dummy_class.new(foo: :bar) }
+      let(:result) { subject.cast_nested_field_value(value, dummy_class, :foo) }
+
+      it "is a new instance of the class with the same attributes" do
+        expect(result).to be_a(dummy_class)
+        expect(result.attributes).to eq(value.attributes)
+        expect(result).to_not equal(value)
+      end
+    end
+
+    context "value is a hash" do
+      let(:value) { { foo: :bar } }
+      let(:result) { subject.cast_nested_field_value(value, dummy_class, :foo) }
+
+      it "is a new instance of the class with the same attributes as the given hash" do
+        expect(result).to be_a(dummy_class)
+        expect(result.attributes).to eq(value)
+      end
+    end
+
+    context "value is nil" do
+      let(:result) { subject.cast_nested_field_value(nil, dummy_class, :foo) }
+
+      it "is a new instance of the class with empty attributes" do
+        expect(result).to be_a(dummy_class)
+        expect(result.attributes).to eq({})
+      end
+    end
+
+    context "value is something else" do
+      it "raises an error" do
+        expect do
+          subject.cast_nested_field_value(Object.new, dummy_class, :foo)
+        end.to raise_error(JsonbAccessor::UnknownValue)
+      end
+    end
+  end
+end