a === b -> identical(a, b)

tests/standalone/io/web_socket_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 
 #import("dart:io");
 #import("dart:scalarlist");
 
 void testRequestResponseClientCloses(
     int totalConnections, int closeStatus, String closeReason) {
   HttpServer server = new HttpServer();
   HttpClient client = new HttpClient();
 
   server.listen("127.0.0.1", 0, backlog: totalConnections);
 
   // Create a web socket handler and set is as the HTTP server default
   // handler.
   WebSocketHandler wsHandler = new WebSocketHandler();
   wsHandler.onOpen = (WebSocketConnection conn) {
     var count = 0;
     conn.onMessage = (Object message) => conn.send(message);
     conn.onClosed = (status, reason) {
-      Expect.equals(closeStatus === null
+      Expect.equals(closeStatus == null
                     ? WebSocketStatus.NO_STATUS_RECEIVED
                     : closeStatus, status);
-      Expect.equals(closeReason === null ? "" : closeReason, reason);
+      Expect.equals(closeReason == null ? "" : closeReason, reason);
     };
   };
   server.defaultRequestHandler = wsHandler.onRequest;
 
   int closeCount = 0;
   String messageText = "Hello, world!";
   for (int i = 0; i < totalConnections; i++) {
     int messageCount = 0;
     HttpClientConnection conn = client.get("127.0.0.1", server.port, "/");
     WebSocketClientConnection wsconn = new WebSocketClientConnection(conn);
     wsconn.onOpen = () => wsconn.send(messageText);
     wsconn.onMessage = (message) {
       messageCount++;
       if (messageCount < 10) {
         Expect.equals(messageText, message);
         wsconn.send(message);
       } else {
         wsconn.close(closeStatus, closeReason);
       }
     };
     wsconn.onClosed = (status, reason) {
-      Expect.equals(closeStatus === null
+      Expect.equals(closeStatus == null
                     ? WebSocketStatus.NO_STATUS_RECEIVED
                     : closeStatus, status);
       Expect.equals("", reason);
       closeCount++;
       if (closeCount == totalConnections) {
         client.shutdown();
         server.close();
       }
     };
   }
@@ skipping 17 matching lines @@
     conn.onMessage = (Object message) {
       messageCount++;
       if (messageCount < 10) {
         Expect.equals(messageText, message);
         conn.send(message);
       } else {
         conn.close(closeStatus, closeReason);
       }
     };
     conn.onClosed = (status, reason) {
-      Expect.equals(closeStatus === null
+      Expect.equals(closeStatus == null
                     ? WebSocketStatus.NO_STATUS_RECEIVED
                     : closeStatus, status);
       Expect.equals("", reason);
       closeCount++;
       if (closeCount == totalConnections) {
         client.shutdown();
         server.close();
       }
     };
     conn.send(messageText);
   };
   server.defaultRequestHandler = wsHandler.onRequest;
 
   for (int i = 0; i < totalConnections; i++) {
     HttpClientConnection conn = client.get("127.0.0.1", server.port, "/");
     WebSocketClientConnection wsconn = new WebSocketClientConnection(conn);
     wsconn.onMessage = (message) => wsconn.send(message);
     wsconn.onClosed = (status, reason) {
-      Expect.equals(closeStatus === null
+      Expect.equals(closeStatus == null
                     ? WebSocketStatus.NO_STATUS_RECEIVED
                     : closeStatus, status);
-      Expect.equals(closeReason === null ? "" : closeReason, reason);
+      Expect.equals(closeReason == null ? "" : closeReason, reason);
     };
   }
 }
 
 
 void testMessageLength(int messageLength) {
   HttpServer server = new HttpServer();
   HttpClient client = new HttpClient();
 
   server.listen("127.0.0.1", 0, backlog: 1);
@@ skipping 213 matching lines @@
   testMessageLength(126);
   testMessageLength(127);
   testMessageLength(65535);
   testMessageLength(65536);
   testNoUpgrade();
   testUsePOST();
   testHashCode(2);
 
   testW3CInterface(2, 3002, "Got tired");
 }