docs/RFC-STORE.md

@@ -90,7 +90,7 @@ for group := range st.GroupsSeq() { ... }
 
 // Events
 ch := st.Watch("group")
-st.OnChange("group", func(key, val string) { ... })
+st.OnChange(func(event store.Event) { ... })
 ```
 
 ---
@@ -136,7 +136,7 @@ func (ss *ScopedStore) GetFrom(group, key string) (string, error) { }
 
 - `Watch(group string) <-chan Event` — returns buffered channel (cap 16), non-blocking sends drop events
 - `Unwatch(group string, ch <-chan Event)` — remove a watcher
-- `OnChange(group, callback)` — synchronous callback in writer goroutine
+- `OnChange(callback)` — synchronous callback in writer goroutine
 - **Deadlock warning:** `notify()` holds `s.mu` read-lock — calling Watch/Unwatch/OnChange from inside a callback will deadlock
 
 ---

docs/index.md

@@ -113,7 +113,7 @@ The entire package lives in a single Go package (`package store`) with three imp
 |------|---------|
 | `doc.go` | Package comment with concrete usage examples |
 | `store.go` | Core `Store` type, CRUD operations (`Get`, `Set`, `SetWithTTL`, `Delete`, `DeleteGroup`), bulk queries (`GetAll`, `All`, `Count`, `CountAll`, `Groups`, `GroupsSeq`), string splitting helpers (`GetSplit`, `GetFields`), template rendering (`Render`), TTL expiry, background purge goroutine |
-| `events.go` | `EventType` constants, `Event` struct, `Watcher` type, `Watch`/`Unwatch` subscription management, `OnChange` callback registration, internal `notify` dispatch |
+| `events.go` | `EventType` constants, `Event` struct, `Watch`/`Unwatch` channel subscriptions, `OnChange` callback registration, internal `notify` dispatch |
 | `scope.go` | `ScopedStore` wrapper for namespace isolation, `QuotaConfig` struct, `NewScoped`/`NewScopedWithQuota` constructors, namespace-local helper delegation, quota enforcement logic |
 
 Tests are organised in corresponding files:
@@ -148,7 +148,7 @@ There are no other direct dependencies. The package uses the Go standard library
 - **`ScopedStore`** -- wraps a `*Store` with an auto-prefixed namespace. Provides the same API surface with group names transparently prefixed.
 - **`QuotaConfig`** -- configures per-namespace limits on total keys and distinct groups.
 - **`Event`** -- describes a single store mutation (type, group, key, value, timestamp).
-- **`Watcher`** -- a channel-based subscription to store events, created by `Watch`. `Events` is the read-only channel to select on.
+- **`Watch`** -- returns a buffered channel subscription to store events. Use `Unwatch(group, events)` to stop delivery and close the channel.
 - **`KeyValue`** -- a simple key-value pair struct, used by the `All` iterator.
 
 ## Sentinel Errors

events.go

@@ -54,7 +54,6 @@ type Event struct {
 // the exact callback later.
 type changeCallbackRegistration struct {
 	registrationID uint64
-	group          string
 	callback       func(Event)
 }
 
@@ -118,51 +117,13 @@ func (storeInstance *Store) Unwatch(group string, events <-chan Event) {
 
 // OnChange registers a synchronous mutation callback.
 // Usage example: `unregister := storeInstance.OnChange(func(event store.Event) { fmt.Println(event.Group, event.Key, event.Value) })`
-// Usage example: `unregister := storeInstance.OnChange("config", func(key, value string) { fmt.Println(key, value) })`
-func (storeInstance *Store) OnChange(arguments ...any) func() {
-	if len(arguments) == 0 {
-		return func() {}
-	}
-
-	var (
-		callbackGroup string
-		callback      func(Event)
-	)
-
-	switch len(arguments) {
-	case 1:
-		switch typedCallback := arguments[0].(type) {
-		case func(Event):
-			callback = typedCallback
-		default:
-			return func() {}
-		}
-	case 2:
-		groupName, ok := arguments[0].(string)
-		if !ok {
-			return func() {}
-		}
-		callbackGroup = groupName
-		switch typedCallback := arguments[1].(type) {
-		case func(Event):
-			callback = typedCallback
-		case func(string, string):
-			callback = func(event Event) {
-				typedCallback(event.Key, event.Value)
-			}
-		default:
-			return func() {}
-		}
-	default:
-		return func() {}
-	}
-
+func (storeInstance *Store) OnChange(callback func(Event)) func() {
 	if callback == nil {
 		return func() {}
 	}
 
 	registrationID := atomic.AddUint64(&storeInstance.nextCallbackRegistrationID, 1)
-	callbackRegistration := changeCallbackRegistration{registrationID: registrationID, group: callbackGroup, callback: callback}
+	callbackRegistration := changeCallbackRegistration{registrationID: registrationID, callback: callback}
 
 	storeInstance.callbacksLock.Lock()
 	storeInstance.callbacks = append(storeInstance.callbacks, callbackRegistration)
@@ -211,9 +172,6 @@ func (storeInstance *Store) notify(event Event) {
 	storeInstance.callbacksLock.RUnlock()
 
 	for _, callback := range callbacks {
-		if callback.group != "" && callback.group != "*" && callback.group != event.Group {
-			continue
-		}
 		callback.callback(event)
 	}
 }

events_test.go

@@ -153,8 +153,11 @@ func TestEvents_OnChange_Good_GroupFilteredCallback(t *testing.T) {
 	defer storeInstance.Close()
 
 	var seen []string
-	unregister := storeInstance.OnChange("config", func(key, value string) {
-		seen = append(seen, key+"="+value)
+	unregister := storeInstance.OnChange(func(event Event) {
+		if event.Group != "config" {
+			return
+		}
+		seen = append(seen, event.Key+"="+event.Value)
 	})
 	defer unregister()