fix(nodecg): avoid intrusive port probe that can break startup on Windows (#26)

src/main/nodecg/process-manager.ts

@@ -248,16 +248,36 @@ function hasReadWriteAccess(candidatePath: string): boolean {
 
 function probePortAvailable(port: number): Promise<boolean> {
   return new Promise((resolve) => {
-    const server = net.createServer();
+    const socket = net.createConnection({ host: "127.0.0.1", port });
+    let resolved = false;
 
-    server.once("error", () => {
+    const complete = (isAvailable: boolean): void => {
-      resolve(false);
+      if (resolved) {
+        return;
+      }
+
+      resolved = true;
+      socket.destroy();
+      resolve(isAvailable);
+    };
+
+    socket.setTimeout(1000);
+
+    socket.once("connect", () => {
+      complete(false);
     });
 
-    server.listen(port, "127.0.0.1", () => {
+    socket.once("timeout", () => {
-      server.close(() => {
+      complete(true);
-        resolve(true);
+    });
-      });
+
+    socket.once("error", (error: NodeJS.ErrnoException) => {
+      if (error.code === "ECONNREFUSED" || error.code === "EHOSTUNREACH") {
+        complete(true);
+        return;
+      }
+
+      complete(false);
     });
   });
 }