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

tests/compiler/dart2js/scanner_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:utf';
 import '../../../sdk/lib/_internal/compiler/implementation/scanner/scannerlib.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/scanner/scanner_implementation.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/util/characters.dart';
 part '../../../sdk/lib/_internal/compiler/implementation/scanner/byte_strings.dart';
 part '../../../sdk/lib/_internal/compiler/implementation/scanner/byte_array_scanner.dart';
 
 Token scan(List<int> bytes) => new ByteArrayScanner(bytes).tokenize();
 
-bool isRunningOnJavaScript() => 1 === 1.0;
+bool isRunningOnJavaScript() => identical(1, 1.0);
 
 main() {
   // Google favorite: "Îñţérñåţîöñåļîžåţîờñ".
   Token token = scan([0xc3, 0x8e, 0xc3, 0xb1, 0xc5, 0xa3, 0xc3, 0xa9, 0x72,
                       0xc3, 0xb1, 0xc3, 0xa5, 0xc5, 0xa3, 0xc3, 0xae, 0xc3,
                       0xb6, 0xc3, 0xb1, 0xc3, 0xa5, 0xc4, 0xbc, 0xc3, 0xae,
                       0xc5, 0xbe, 0xc3, 0xa5, 0xc5, 0xa3, 0xc3, 0xae, 0xe1,
                       0xbb, 0x9d, 0xc3, 0xb1, $EOF]);
   Expect.stringEquals("Îñţérñåţîöñåļîžåţîờñ", token.value.slowToString());
 
@@ skipping 31 matching lines @@
   // "#!"
   token = scan([0x23, 0x21, $EOF]);
   Expect.equals(token.info, EOF_INFO); // Treated as a comment.
 
   // Regression test for issue 1761.
   // "#! Hello, World!"
   token = scan([0x23, 0x21, 0x20, 0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x2c, 0x20,
                 0x57, 0x6f, 0x72, 0x6c, 0x64, 0x21, $EOF]);
   Expect.equals(token.info, EOF_INFO); // Treated as a comment.
 }