fix(ngModel): do not reset bound date objects

Closes angular#6666

Author: btford

src/ng/directive/input.js

@@ -1009,7 +1009,7 @@ function baseInputType(scope, element, attr, ctrl, $sniffer, $browser) {
   };
 }
 
-function weekParser(isoWeek) {
+function weekParser(isoWeek, existingDate) {
   if (isDate(isoWeek)) {
     return isoWeek;
   }
@@ -1022,16 +1022,33 @@ function weekParser(isoWeek) {
           week = +parts[2],
           firstThurs = getFirstThursdayOfYear(year),
           addDays = (week - 1) * 7;
+
+      if (existingDate) {
+        return new Date(year, 0, firstThurs.getDate() + addDays,
+            existingDate.getHours(),
+            existingDate.getMinutes(),
+            existingDate.getSeconds(),
+            existingDate.getMilliseconds());
+      }
       return new Date(year, 0, firstThurs.getDate() + addDays);
     }
   }
 
   return NaN;
 }
 
+var DATE_METHOD_MAPPING = {
+  yyyy: 'FullYear',
+  MM: 'Month',
+  dd: 'Date',
+  HH: 'Hours',
+  mm: 'Minutes',
+  ss: 'Seconds'
+};
+
 function createDateParser(regexp, mapping) {
-  return function(iso) {
-    var parts, map;
+  return function(iso, date, timezone) {
+    var parts, map, getterPrefix;
 
     if (isDate(iso)) {
       return iso;
@@ -1050,6 +1067,16 @@ function createDateParser(regexp, mapping) {
             map[mapping[index]] = +part;
           }
         });
+        if (date) {
+          getterPrefix = timezone === 'UTC' ? 'getUTC' : 'get';
+
+          forEach(DATE_METHOD_MAPPING, function(methodName, part) {
+            if (mapping.indexOf(part) === -1) {
+              // months are 0-indexed
+              map[part] = date[getterPrefix + methodName]() + (part === 'MM');
+            }
+          });
+        }
         return new Date(map.yyyy, map.MM - 1, map.dd, map.HH, map.mm, map.ss || 0);
       }
     }
@@ -1068,7 +1095,7 @@ function createDateInputType(type, regexp, parseDate, format) {
     ctrl.$parsers.push(function(value) {
       if (ctrl.$isEmpty(value)) return null;
       if (regexp.test(value)) {
-        var parsedDate = parseDate(value);
+        var parsedDate = parseDate(value, ctrl.$modelValue, timezone);
         if (timezone === 'UTC') {
           parsedDate.setMinutes(parsedDate.getMinutes() - parsedDate.getTimezoneOffset());
         }

test/ng/directive/inputSpec.js

@@ -2062,6 +2062,17 @@ describe('input', function() {
       expect(scope.form.alias.$error.month).toBeTruthy();
     });
 
+    it('should only change the month of a bound date', function() {
+      compileInput('<input type="month" ng-model="value" ng-model-options="{timezone: \'UTC\'}" />');
+
+      scope.$apply(function() {
+        scope.value = new Date(Date.UTC(2013, 7, 1, 1, 0, 0));
+      });
+      changeInputValueTo('2013-12');
+      expect(+scope.value).toBe(Date.UTC(2013, 11, 1, 1, 0, 0));
+      expect(inputElm.val()).toBe('2013-12');
+    });
+
     describe('min', function (){
       beforeEach(function (){
         compileInput('<input type="month" ng-model="value" name="alias" min="2013-01" />');
@@ -2124,6 +2135,18 @@ describe('input', function() {
       expect(inputElm.val()).toBe('2013-W02');
     });
 
+    it('should not affect the hours or minutes of a bound date', function (){
+      compileInput('<input type="week" ng-model="secondWeek"/>');
+
+      scope.$apply(function(){
+        scope.secondWeek = new Date(2013, 0, 11, 1, 0, 0);
+      });
+
+      changeInputValueTo('2013-W03');
+
+      expect(+scope.secondWeek).toBe(+new Date(2013, 0, 17, 1, 0, 0));
+    });
+
     it('should set the model undefined if the input is an invalid week string', function () {
       compileInput('<input type="week" ng-model="value"/>');
 
@@ -2549,6 +2572,17 @@ describe('input', function() {
       expect(scope.form.alias.$error.time).toBeTruthy();
     });
 
+    it('should only change hours and minute of a bound date', function() {
+      compileInput('<input type="time" ng-model="value"" />');
+
+      scope.$apply(function(){
+        scope.value = new Date(2013, 2, 3, 1, 0, 0);
+      });
+
+      changeInputValueTo('01:02');
+      expect(+scope.value).toBe(+new Date(2013, 2, 3, 1, 2, 0));
+    });
+
     describe('min', function (){
       beforeEach(function (){
         compileInput('<input type="time" ng-model="value" name="alias" min="09:30:00" />');