From 37159d31bd1f1765b0978b104f58056d00a9713c Mon Sep 17 00:00:00 2001
From: realrasengan <andrew@joseon.com>
Date: Mon, 30 Mar 2026 16:19:17 -0700
Subject: [PATCH] WASM: use persistent writer, fix connection lost from lock
 churn

---
 cmd/mosh-wasm/webtransport.go | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/cmd/mosh-wasm/webtransport.go b/cmd/mosh-wasm/webtransport.go
index 51fc7c2..f4d508e 100644
--- a/cmd/mosh-wasm/webtransport.go
+++ b/cmd/mosh-wasm/webtransport.go
@@ -12,6 +12,7 @@ import (
 // wtConn wraps a browser WebTransport connection as a mosh.Conn.
 type wtConn struct {
 	transport js.Value
+	writer    js.Value // persistent writable stream writer
 	incoming  chan []byte
 	done      chan struct{}
 	once      sync.Once
@@ -56,8 +57,11 @@ func dialWebTransport(url string) (*wtConn, error) {
 	onReady.Release()
 	onFail.Release()
 
+	writer := wt.Get("datagrams").Get("writable").Call("getWriter")
+
 	c := &wtConn{
 		transport: wt,
+		writer:    writer,
 		incoming:  make(chan []byte, 256),
 		done:      make(chan struct{}),
 	}
@@ -132,11 +136,9 @@ func (c *wtConn) Read(b []byte) (int, error) {
 }
 
 func (c *wtConn) Write(b []byte) (int, error) {
-	writer := c.transport.Get("datagrams").Get("writable").Call("getWriter")
 	arr := js.Global().Get("Uint8Array").New(len(b))
 	js.CopyBytesToJS(arr, b)
-	writer.Call("write", arr)
-	writer.Call("releaseLock")
+	c.writer.Call("write", arr)
 	return len(b), nil
 }