logger: adjustment for the new Done function - use nil instead of emp…

…ty func

middleware/logger/config.go

@@ -20,7 +20,7 @@ type Config struct {
 	// Done is a function that is called after the log string for a request is written to Output,
 	// and pass the log string as parameter.
 	//
-	// Optional. Default: a function that does nothing.
+	// Optional. Default: nil
 	Done func(c *fiber.Ctx, logString []byte)
 
 	// tagFunctions defines the custom tag action
@@ -69,7 +69,7 @@ type LogFunc func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extr
 // ConfigDefault is the default config
 var ConfigDefault = Config{
 	Next:         nil,
-	Done:         func(c *fiber.Ctx, logString []byte) {},
+	Done:         nil,
 	Format:       "[${time}] ${status} - ${latency} ${method} ${path}\n",
 	TimeFormat:   "15:04:05",
 	TimeZone:     "Local",

middleware/logger/logger.go

@@ -156,7 +156,9 @@ func New(config ...Config) fiber.Handler {
 			// Write buffer to output
 			_, _ = cfg.Output.Write(buf.Bytes())
 
-			cfg.Done(c, buf.Bytes())
+			if cfg.Done != nil {
+				cfg.Done(c, buf.Bytes())
+			}
 
 			// Put buffer back to pool
 			bytebufferpool.Put(buf)
@@ -194,7 +196,9 @@ func New(config ...Config) fiber.Handler {
 		}
 		mu.Unlock()
 
-		cfg.Done(c, buf.Bytes())
+		if cfg.Done != nil {
+			cfg.Done(c, buf.Bytes())
+		}
 
 		// Put buffer back to pool
 		bytebufferpool.Put(buf)