refactor: replace fmt.Errorf with MessageTooBigError

read.go

@@ -17,6 +17,8 @@ import (
 	"github.com/coder/websocket/internal/util"
 )
 
+var ErrMessageTooBig = errors.New("websocket: message too big")
+
 // Reader reads from the connection until there is a WebSocket
 // data message to be read. It will handle ping, pong and close frames as appropriate.
 //
@@ -520,7 +522,7 @@ func (lr *limitReader) Read(p []byte) (int, error) {
 	}
 
 	if lr.n == 0 {
-		err := fmt.Errorf("read limited at %v bytes", lr.limit.Load())
+		err := fmt.Errorf("%w: %d bytes", ErrMessageTooBig, lr.limit.Load())
 		lr.c.writeError(StatusMessageTooBig, err)
 		return 0, err
 	}

ws_js.go

@@ -19,6 +19,8 @@ import (
 	"github.com/coder/websocket/internal/wsjs"
 )
 
+var ErrMessageTooBig = errors.New("websocket: message too big")
+
 // opcode represents a WebSocket opcode.
 type opcode int
 
@@ -144,7 +146,7 @@ func (c *Conn) Read(ctx context.Context) (MessageType, []byte, error) {
 	}
 	readLimit := c.msgReadLimit.Load()
 	if readLimit >= 0 && int64(len(p)) > readLimit {
-		err := fmt.Errorf("read limited at %v bytes", c.msgReadLimit.Load())
+		err := fmt.Errorf("%w: %d bytes", ErrMessageTooBig, c.msgReadLimit.Load())
 		c.Close(StatusMessageTooBig, err.Error())
 		return 0, nil, err
 	}