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

samples/swarm/swarm_ui_lib/util/Uri.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.
 
 /**
  * A parsed URI, inspired by:
  * http://closure-library.googlecode.com/svn/docs/class_goog_Uri.html
  */
 class Uri extends uri.Uri {
   /**
    * Parses a URL query string into a map. Because you can have multiple values
    * for the same parameter name, each parameter name maps to a list of
    * values. For example, '?a=b&c=d&a=e' would be parsed as
    * [{'a':['b','e'],'c':['d']}].
    */
   // TODO(jmesserly): consolidate with new Uri.fromString(...)
   static Map<String, List<String>> parseQuery(String queryString) {
     final queryParams = new Map<String, List<String>>();
     if (queryString.startsWith('?')) {
       final params = queryString.substring(1, queryString.length).split('&');
       for (final param in params) {
         List<String> parts = param.split('=');
         if (parts.length == 2) {
           // TODO(hiltonc) the name and value should be URL decoded.
           String name = parts[0];
           String value = parts[1];
 
           // Create a list of values for this name if not yet done.
           List values = queryParams[name];
-          if (values === null) {
+          if (values == null) {
             values = new List();
             queryParams[name] = values;
           }
 
           values.add(value);
         }
       }
     }
     return queryParams;
   }
@@ skipping 27 matching lines @@
     return component.replaceAll('%3A', ':')
                     .replaceAll('%2F', '/')
                     .replaceAll('%3F', '?')
                     .replaceAll('%3D', '=')
                     .replaceAll('%26', '&')
                     .replaceAll('%20', ' ');
   }
 
   Uri.fromString(String uriString) : super.fromString(uriString);
 }