Avoid browser warnings when closing unestablished WebSocket (#799)

* Avoid browser warnings when closing unestablished WebSocket

* PR link

wasm-node/CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Fixed
 
 - Fix not absorbing the JavaScript exception triggered by the browser when connecting to a `ws://` node when smoldot is embedded in a web page served over `https://`. ([#795](https://github.com/smol-dot/smoldot/pull/795), [#800](https://github.com/smol-dot/smoldot/pull/800))
+- Smoldot no longer calls `close()` on WebSockets that aren't fully established yet (even though it is legal to do so according to the WHATWG specification) in order to avoid browsers printing warnings in the console when you do so. ([#799](https://github.com/smol-dot/smoldot/pull/799))
 
 ## 1.0.10 - 2023-06-19
 

wasm-node/javascript/src/no-auto-bytecode-browser.ts

@@ -151,7 +151,17 @@ function connect(config: ConnectionConfig): Connection {
                     connection.onclose = null;
                     connection.onmessage = null;
                     connection.onerror = null;
-                    connection.close();
+
+                    // According to the WebSocket specification, calling `close()` when a WebSocket
+                    // isn't fully opened yet is completely legal and seemingly a normal thing to
+                    // do (see <https://websockets.spec.whatwg.org/#dom-websocket-close>).
+                    // Unfortunately, browsers print a warning in the console if you do that. To
+                    // avoid these warnings, we only call `close()` if the connection is fully
+                    // opened. According to <https://websockets.spec.whatwg.org/#garbage-collection>,
+                    // removing all the event listeners will cause the WebSocket to be garbage
+                    // collected, which should have the same effect as `close()`.
+                    if (connection.readyState == WebSocket.OPEN)
+                        connection.close();
                 }
 
                 connection = null;