Catch sync errors while starting HTTP server

Reviewed By: lblasa

Differential Revision: D50636260

fbshipit-source-id: f23fb2005c779b87122ae34bfdd9371d8bdec8b4

desktop/flipper-server-core/src/app-connectivity/ServerRSocket.tsx

@@ -47,6 +47,7 @@ class ServerRSocket extends ServerWebSocketBase {
   start(port: number, sslConfig?: SecureServerConfig): Promise<number> {
     const self = this;
     return new Promise((resolve, reject) => {
+      try {
         // eslint-disable-next-line prefer-const
         let rawServer: RSocketServer<any, any> | undefined;
         const serverFactory = (onConnect: (socket: Socket) => void) => {
@@ -78,6 +79,9 @@ class ServerRSocket extends ServerWebSocketBase {
           }),
         });
         rawServer.start();
+      } catch (e) {
+        reject(e);
+      }
     });
   }
 

desktop/flipper-server-core/src/app-connectivity/ServerWebSocket.tsx

@@ -49,6 +49,7 @@ class ServerWebSocket extends ServerWebSocketBase {
 
   async start(port: number, sslConfig?: SecureServerConfig): Promise<number> {
     const assignedPort = await new Promise<number>((resolve, reject) => {
+      try {
         const server = sslConfig
           ? createHttpsServer(sslConfig)
           : createHttpServer();
@@ -89,6 +90,9 @@ class ServerWebSocket extends ServerWebSocketBase {
 
           resolve((server.address() as AddressInfo).port);
         });
+      } catch (e) {
+        reject(e);
+      }
     });
 
     assertNotNull(this.wsServer);