service.go

@@ -487,6 +487,9 @@ func (s *Service) getEffectiveContextExtra(data any) map[string]any {
 			switch key {
 			case "Context", "Gender", "Location", "Formality":
 				continue
+			case "Extra", "extra", "Extras", "extras":
+				mergeContextExtra(extra, value)
+				continue
 			default:
 				extra[key] = value
 			}
@@ -500,6 +503,29 @@ func (s *Service) getEffectiveContextExtra(data any) map[string]any {
 	}
 }
 
+func mergeContextExtra(dst map[string]any, value any) {
+	if dst == nil || value == nil {
+		return
+	}
+	switch extra := value.(type) {
+	case map[string]any:
+		for key, item := range extra {
+			dst[key] = item
+		}
+	case map[string]string:
+		for key, item := range extra {
+			dst[key] = item
+		}
+	case *TranslationContext:
+		if extra == nil || len(extra.Extra) == 0 {
+			return
+		}
+		for key, item := range extra.Extra {
+			dst[key] = item
+		}
+	}
+}
+
 func (s *Service) getEffectiveFormality(data any) Formality {
 	if ctx, ok := data.(*TranslationContext); ok && ctx != nil {
 		if ctx.Formality != FormalityNeutral {

service_test.go

@@ -106,6 +106,28 @@ func TestServiceTPluralMessage(t *testing.T) {
 	}
 }
 
+func TestServiceTMapContextNestedExtra(t *testing.T) {
+	svc, err := New()
+	if err != nil {
+		t.Fatalf("New() failed: %v", err)
+	}
+	SetDefault(svc)
+
+	svc.AddMessages("en", map[string]string{
+		"welcome._nav._scope._admin": "Admin navigation",
+	})
+
+	got := svc.T("welcome", map[string]any{
+		"Context": "nav",
+		"Extra": map[string]any{
+			"Scope": "admin",
+		},
+	})
+	if got != "Admin navigation" {
+		t.Fatalf("T(welcome, nested extra) = %q, want %q", got, "Admin navigation")
+	}
+}
+
 func TestServiceRaw(t *testing.T) {
 	svc, err := New()
 	if err != nil {