fix(dateFilter): allow negative millisecond value strings

Author: Henning Teek

src/ng/filter/filters.js

@@ -260,7 +260,7 @@ var DATE_FORMATS = {
 };
 
 var DATE_FORMATS_SPLIT = /((?:[^yMdHhmsaZE']+)|(?:'(?:[^']|'')*')|(?:E+|y+|M+|d+|H+|h+|m+|s+|a|Z))(.*)/,
-    NUMBER_STRING = /^\d+$/;
+    NUMBER_STRING = /^\-?\d+$/;
 
 /**
  * @ngdoc filter

test/ng/filter/filtersSpec.js

@@ -246,6 +246,10 @@ describe('filters', function() {
                       toEqual('September 03, 1');
     });
 
+    it('should accept negative numbers as strings', function() {
+      expect(date('-1')).toEqual('Dec 31, 1969');
+    });
+
     it('should format timezones correctly (as per ISO_8601)', function() {
       //Note: TzDate's first argument is offset, _not_ timezone.
       var utc       = new angular.mock.TzDate( 0, '2010-09-03T12:05:08.000Z');