Support proc as source option

lib/invalid_model/each_serializer.rb

@@ -48,10 +48,15 @@ def meta
     end
 
     def source
-      return @options[:source] if @options.key?(:source)
-      return if attribute == :base
+      if @options[:source].respond_to?(:call)
+        @options[:source].call resource, error
+      elsif @options.key?(:source)
+        @options[:source]
+      else
+        return if attribute == :base
 
-      {pointer: "/data/attributes/#{attribute}"}
+        {pointer: "/data/attributes/#{attribute}"}
+      end
     end
 
     def status

spec/invalid_model/serializer_spec.rb

@@ -1,11 +1,12 @@
 # require 'invalid_model/serializer'
 
 RSpec.describe InvalidModel::Serializer do
-  subject(:hash) { described_class.new(model.tap(&:valid?)).serializable_hash }
+  subject(:hash) { described_class.new(model.tap(&:valid?), options).serializable_hash }
 
   let(:json) { MultiJson.dump(hash) }
+  let(:options) { {} }
 
-  context 'when the model multiple errors' do
+  context 'when the model has multiple errors' do
     let(:model) { DummyModel.new(code: '?', size: 'wrong') }
 
     it 'has 4 errors' do
@@ -81,6 +82,26 @@
         JSON
       ).at_path('errors')
     end
+
+    context 'when injecting a custom source' do
+      let(:options) { {source: ->(_m, e) { {'pointer' => "/#{e.attribute}"} }} }
+
+      it 'renders correct json' do
+        expect(json).to be_json_eql(<<~JSON).at_path('errors/0')
+          {
+            "code": "validation_error/invalid",
+            "detail": "Code is invalid",
+            "meta": {
+              "value": "?"
+            },
+            "source": {
+              "pointer": "/code"
+            },
+            "status": "400"
+          }
+        JSON
+      end
+    end
   end
 
   context 'when the model has a custom error' do