fix(dateparser): do not parse if no format specified

Fixes #2159
Fixes #2137
Closes #2162

Author: bekos

src/dateparser/dateparser.js

@@ -49,7 +49,7 @@ angular.module('ui.bootstrap.dateparser', [])
     }
   };
 
-  this.createParser = function(format) {
+  function createParser(format) {
     var map = [], regex = format.split('');
 
     angular.forEach(formatCodeToRegex, function(data, code) {
@@ -74,17 +74,17 @@ angular.module('ui.bootstrap.dateparser', [])
       regex: new RegExp('^' + regex.join('') + '$'),
       map: orderByFilter(map, 'index')
     };
-  };
+  }
 
   this.parse = function(input, format) {
-    if ( !angular.isString(input) ) {
+    if ( !angular.isString(input) || !format ) {
       return input;
     }
 
     format = $locale.DATETIME_FORMATS[format] || format;
 
     if ( !this.parsers[format] ) {
-      this.parsers[format] = this.createParser(format);
+      this.parsers[format] = createParser(format);
     }
 
     var parser = this.parsers[format],

src/dateparser/test/dateparser.spec.js

@@ -93,4 +93,14 @@ describe('date parser', function () {
       expect(dateParser.parse('November 31, 2013', 'MMMM d, yyyy')).toBeUndefined();
     });
   });
+
+  it('should not parse non-string inputs', function() {
+    expect(dateParser.parse(123456, 'dd.MM.yyyy')).toBe(123456);
+    var date = new Date();
+    expect(dateParser.parse(date, 'dd.MM.yyyy')).toBe(date);
+  });
+
+  it('should not parse if no format is specified', function() {
+    expect(dateParser.parse('21.08.1951', '')).toBe('21.08.1951');
+  });
 });