Commit 58f695c

@@ -17,6 +17,15 @@ func (a *Aggregator) Subscribe(event Event, f Subscription) {
 	a.subscriptions[event] = append(a.subscriptions[event], f)
 }
 
+func (a *Aggregator) SubscribeTo[T any](event Event, f func(T)) {
+	wrapper := func(message any) {
+		if typedMessage, ok := message.(T); ok {
+			f(typedMessage)
+		}
+	}
+	a.Subscribe(event, wrapper)
+}
+
 func (a *Aggregator) Publish(event Event, message any) {
 	for _, subscription := range a.subscriptions[event] {
 		subscription(message)

@@ -9,44 +9,58 @@ import (
 func TestEventAggregator(t *testing.T) {
 	t.Run("Publish", func(t *testing.T) {
 		t.Run("without any subscribers", func(t *testing.T) {
-			events := New()
+			aggregator := New()
 
-			events.Publish("announcements.engineering", "Business, Business, Business... Numbers!")
+			aggregator.Publish("announcements.engineering", "Business, Business, Business... Numbers!")
 		})
 
 		t.Run("with a single subscriber", func(t *testing.T) {
-			events := New()
+			aggregator := New()
 			called := false
 
-			events.Subscribe("announcement", func(message any) {
+			aggregator.Subscribe("announcement", func(message any) {
 				called = true
 				assert.Equal(t, "Hello", message)
 			})
 
-			events.Publish("announcement", "Hello")
+			aggregator.Publish("announcement", "Hello")
 
 			assert.True(t, called)
 		})
 
 		t.Run("with multiple subscribers", func(t *testing.T) {
-			events := New()
+			aggregator := New()
 			called := map[int]bool{}
 
-			events.Subscribe("announcement", func(message any) {
+			aggregator.Subscribe("announcement", func(message any) {
 				called[0] = true
 				assert.Equal(t, "Greetings", message)
 			})
 
-			events.Subscribe("announcement", func(message any) {
+			aggregator.Subscribe("announcement", func(message any) {
 				called[1] = true
 				assert.Equal(t, "Greetings", message)
 			})
 
-			events.Publish("announcement", "Greetings")
+			aggregator.Publish("announcement", "Greetings")
 
 			assert.Equal(t, 2, len(called))
 			assert.True(t, called[0])
 			assert.True(t, called[1])
 		})
+
+		t.Run("with a strongly typed payload", func(t *testing.T) {
+			aggregator := New()
+
+			type announcement struct {
+				message string
+			}
+
+			aggregator.SubscribeTo("announcement", func(payload announcement) {
+				assert.Equal(t, "Hello", payload.message)
+			})
+
+			aggregator.Publish("announcement", announcement{message: "Hello"})
+		})
 	})
 }