lib/dry/events/publisher.rb in dry-events-0.1.1 vs lib/dry/events/publisher.rb in dry-events-0.2.0

@@ -17,10 +17,23 @@
       def initialize(id)
         super("publisher with id #{id.inspect} already registered as: #{Publisher.registry[id]}")
       end
     end
 
+    # @api public
+    InvalidSubscriberError = Class.new(StandardError) do
+      # @api private
+      def initialize(object_or_event_id)
+        case object_or_event_id
+        when String, Symbol
+          super("you are trying to subscribe to an event: `#{object_or_event_id}` that has not been registered")
+        else
+          super("you try use subscriber object that will never be executed")
+        end
+      end
+    end
+
     # Extension used for classes that can publish events
     #
     # @example
     #   class AppEvents
     #     include Dry::Events::Publisher[:app]
@@ -188,17 +201,22 @@
         #
         # @return [Object] self
         #
         # @api public
         def subscribe(object_or_event_id, filter_hash = EMPTY_HASH, &block)
-          filter = Filter.new(filter_hash)
+          if __bus__.can_handle?(object_or_event_id)
+            filter = Filter.new(filter_hash)
 
-          if block
-            __bus__.subscribe(object_or_event_id, filter, &block)
+            if block
+              __bus__.subscribe(object_or_event_id, filter, &block)
+            else
+              __bus__.attach(object_or_event_id, filter)
+            end
+
+            self
           else
-            __bus__.attach(object_or_event_id, filter)
+            raise InvalidSubscriberError, object_or_event_id
           end
-          self
         end
 
         # Unsubscribe a listener
         #
         # @param [Object] listener The listener object