Raise NoMethodError if raise_on_missing option is enabled

README.md

@@ -62,6 +62,23 @@ ros = RecursiveOpenStruct.new(h, preserve_original_keys: true)
 ros.to_h # => { 'fear' => 'is', 'the' => 'mindkiller' }
 ```
 
+### Optional: Raise error on missing attribute
+
+This option allows to raise an error if you try to call an attribute you didn't specify in hash
+
+```ruby
+h = { 'fear' => 'is', 'the' => 'mindkiller' } }
+ros = RecursiveOpenStruct.new(h, raise_on_missing: true)
+ros.undefined # => undefined method `undefined' for #<RecursiveOpenStruct fear="is", the="mindkiller">
+```
+
+The default behaviour returns nil
+
+```ruby
+h = { 'fear' => 'is', 'the' => 'mindkiller' } }
+ros = RecursiveOpenStruct.new(h)
+ros.undefined # => nil
+```
 
 ## Installation
 

lib/recursive_open_struct.rb

@@ -23,7 +23,8 @@ def self.default_options
     {
       mutate_input_hash: false,
       recurse_over_arrays: false,
-      preserve_original_keys: false
+      preserve_original_keys: false,
+      raise_on_missing: false
     }
   end
 
@@ -124,6 +125,10 @@ def method_missing(mid, *args)
       if @table.key?(_get_key_from_table_(key))
         new_ostruct_member!(key)
         public_send(mid)
+      elsif @options[:raise_on_missing]
+        err = NoMethodError.new "undefined method `#{mid}' for #{self}", mid, args
+        err.set_backtrace caller(1)
+        raise err
       end
     else
       err = NoMethodError.new "undefined method `#{mid}' for #{self}", mid, args

spec/recursive_open_struct/indifferent_access_spec.rb

@@ -160,6 +160,30 @@
         end
       end
 
+      context 'when undefined method' do
+        context 'when raise_on_missing is enabled' do
+          subject(:recursive) { RecursiveOpenStruct.new(recursive_hash, raise_on_missing: true) }
+          let(:recursive_hash) { {:foo => [ {'bar' => [ { 'foo' => :bar} ] } ] } }
+
+          specify 'raises NoMethodError' do
+            expect {
+              recursive.undefined_method
+            }.to raise_error(NoMethodError)
+          end
+        end
+
+        context 'when raise_on_missing is disabled' do
+          context 'preserves the original keys' do
+            subject(:recursive) { RecursiveOpenStruct.new(recursive_hash) }
+            let(:recursive_hash) { {:foo => [ {'bar' => [ { 'foo' => :bar} ] } ] } }
+
+            specify 'returns nil' do
+              expect(recursive.undefined_method).to be_nil
+            end
+          end
+        end
+      end
+
     end
 
   end