node:net: throw ERR_SOCKET_BAD_PORT for Server.listen("") instead of binding an ephemeral port

src/js/node/net.ts

@@ -3237,10 +3237,6 @@ Server.prototype.getConnections = function getConnections(callback) {
 
 Server.prototype.listen = function listen(port, hostname, onListen) {
   const argsLength = arguments.length;
-  if (typeof port === "string") {
-    const numPort = Number(port);
-    if (!Number.isNaN(numPort)) port = numPort;
-  }
   let backlog;
   let path;
   let exclusive = false;
@@ -3249,8 +3245,10 @@ Server.prototype.listen = function listen(port, hostname, onListen) {
   let readableAll = false;
   let writableAll = false;
   let fd;
-  //port is actually path
-  if (typeof port === "string") {
+  // Match Node's normalizeArgs: a positional string argument is a pipe path
+  // only when isPipeName() is true; otherwise (including "" and "  ") it is
+  // treated as a port and flows to validatePort which rejects empty strings.
+  if (isPipeName(port)) {
     if (Number.isSafeInteger(hostname)) {
       if (hostname > 0) {
         //hostname is backlog

src/jsc/bindings/NodeValidator.cpp

@@ -297,6 +297,7 @@ JSC_DEFINE_HOST_FUNCTION(jsFunction_validatePort, (JSC::JSGlobalObject * globalO
             if (c >= 0x2029 && c <= 0x2029) return true;
             if (c >= 0x202F && c <= 0x202F) return true;
             if (c >= 0x205F && c <= 0x205F) return true;
+            if (c >= 0x3000 && c <= 0x3000) return true;
 
             // LineTerminator ::
             if (c == 0x000A) return true; // <LF>

test/js/node/net/node-net-server.test.ts

@@ -471,6 +471,29 @@ describe("net.createServer events", () => {
     );
   });
 
+  it.each(["", " ", "   ", "\t", "\u3000"])(
+    "should throw ERR_SOCKET_BAD_PORT synchronously for listen(%j) instead of binding an ephemeral TCP port",
+    port => {
+      const server = createServer();
+      try {
+        let err: any;
+        try {
+          server.listen(port, () => {});
+        } catch (e) {
+          err = e;
+        }
+        expect(err).toBeDefined();
+        expect({ code: err.code, message: err.message }).toEqual({
+          code: "ERR_SOCKET_BAD_PORT",
+          message: expect.stringContaining("options.port"),
+        });
+        expect(server.listening).toBe(false);
+      } finally {
+        if (server.listening) server.close();
+      }
+    },
+  );
+
   it("should call abort with signal", done => {
     const { mustCall, mustNotCall } = createCallCheckCtx(done);