Adding isNotEmpty property to collection and string.

sdk/lib/html/dart2js/html_dart2js.dart

 /// The Dart HTML library.
 library dart.dom.html;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:_collection-dev' hide Symbol;
 import 'dart:html_common';
 import 'dart:indexed_db';
 import 'dart:isolate';
 import 'dart:json' as json;
@@ skipping 19753 matching lines @@
   Iterable<String> get values {
     final values = [];
     forEach((k, v) => values.add(v));
     return values;
   }
 
   int get length => $dom_length;
 
   bool get isEmpty => $dom_key(0) == null;
 
+  bool get isNotEmpty => !isEmpty;
+
   @JSName('length')
   @DomName('Storage.length')
   @DocsEditable
   final int $dom_length;
 
   @JSName('clear')
   @DomName('Storage.clear')
   @DocsEditable
   void $dom_clear() native;
 
@@ skipping 5078 matching lines @@
   }
 
   /**
    * Returns true if there is no {key, value} pair in the map.
    */
   bool get isEmpty {
     return length == 0;
   }
 
   /**
+   * Returns true if there is at least one {key, value} pair in the map.
+   */
+  bool get isNotEmpty => !isEmpty;
+
+  /**
    * Checks to see if the node should be included in this map.
    */
   bool _matches(Node node);
 }
 
 /**
  * Wrapper to expose [Element.attributes] as a typed map.
  */
 class _ElementAttributeMap extends _AttributeMap {
 
@@ skipping 126 matching lines @@
       }
     });
     return values;
   }
 
   int get length => keys.length;
 
   // TODO: Use lazy iterator when it is available on Map.
   bool get isEmpty => length == 0;
 
+  bool get isNotEmpty => !isEmpty;
+
   // Helpers.
   String _attr(String key) => 'data-$key';
   bool _matches(String key) => key.startsWith('data-');
   String _strip(String key) => key.substring(5);
 }
 // 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.
 
 
@@ skipping 4245 matching lines @@
       _position = nextPosition;
       return true;
     }
     _current = null;
     _position = _array.length;
     return false;
   }
 
   T get current => _current;
 }