refactor: simplify Datastar configuration API

Flatten DatastarConfig struct into Options (DatastarContent, DatastarPath)
and replace datastarHandlerRegistered bool with sync.Once for thread safety.

configuration.go

@@ -2,17 +2,6 @@ package via
 
 import "github.com/alexedwards/scs/v2"
 
-// DatastarConfig configures a custom Datastar.js script.
-type DatastarConfig struct {
-	// Content is the Datastar.js script content.
-	// If nil, the embedded default is used.
-	Content []byte
-
-	// Path is the URL path where the script is served.
-	// Defaults to "/_datastar.js" if empty.
-	Path string
-}
-
 type LogLevel int
 
 const (
@@ -49,7 +38,11 @@ type Options struct {
 	// passing it (lifetime, cookie settings, store, etc).
 	SessionManager *scs.SessionManager
 
-	// Datastar configures a custom Datastar.js script.
-	// If nil, Via uses its embedded default.
-	Datastar *DatastarConfig
+	// DatastarContent is the Datastar.js script content.
+	// If nil, the embedded default is used.
+	DatastarContent []byte
+
+	// DatastarPath is the URL path where the script is served.
+	// Defaults to "/_datastar.js" if empty.
+	DatastarPath string
 }

via.go

@@ -39,10 +39,10 @@ type V struct {
 	documentHeadIncludes      []h.H
 	documentFootIncludes      []h.H
 	devModePageInitFnMap      map[string]func(*Context)
-	sessionManager            *scs.SessionManager
-	datastarPath              string
-	datastarContent           []byte
-	datastarHandlerRegistered bool
+	sessionManager  *scs.SessionManager
+	datastarPath    string
+	datastarContent []byte
+	datastarOnce    sync.Once
 }
 
 func (v *V) logFatal(format string, a ...any) {
@@ -111,13 +111,11 @@ func (v *V) Config(cfg Options) {
 	if cfg.SessionManager != nil {
 		v.sessionManager = cfg.SessionManager
 	}
-	if cfg.Datastar != nil {
-		if cfg.Datastar.Content != nil {
-			v.datastarContent = cfg.Datastar.Content
-		}
-		if cfg.Datastar.Path != "" {
-			v.datastarPath = cfg.Datastar.Path
-		}
+	if cfg.DatastarContent != nil {
+		v.datastarContent = cfg.DatastarContent
+	}
+	if cfg.DatastarPath != "" {
+		v.datastarPath = cfg.DatastarPath
 	}
 }
 
@@ -271,13 +269,11 @@ func (v *V) HTTPServeMux() *http.ServeMux {
 }
 
 func (v *V) ensureDatastarHandler() {
-	if v.datastarHandlerRegistered {
-		return
-	}
-	v.datastarHandlerRegistered = true
-	v.mux.HandleFunc("GET "+v.datastarPath, func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "application/javascript")
-		_, _ = w.Write(v.datastarContent)
+	v.datastarOnce.Do(func() {
+		v.mux.HandleFunc("GET "+v.datastarPath, func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Content-Type", "application/javascript")
+			_, _ = w.Write(v.datastarContent)
+		})
 	})
 }
 

via_test.go

@@ -45,9 +45,7 @@ func TestCustomDatastarContent(t *testing.T) {
 	customScript := []byte("// Custom Datastar Script")
 	v := New()
 	v.Config(Options{
-		Datastar: &DatastarConfig{
-			Content: customScript,
-		},
+		DatastarContent: customScript,
 	})
 	v.Page("/", func(c *Context) {
 		c.View(func() h.H { return h.Div() })
@@ -65,9 +63,7 @@ func TestCustomDatastarContent(t *testing.T) {
 func TestCustomDatastarPath(t *testing.T) {
 	v := New()
 	v.Config(Options{
-		Datastar: &DatastarConfig{
-			Path: "/assets/datastar.js",
-		},
+		DatastarPath: "/assets/datastar.js",
 	})
 	v.Page("/test", func(c *Context) {
 		c.View(func() h.H { return h.Div() })