Only use day, month, year provided by datepicker (#11773) (#11883)

* Only use day, month, year provided by datepicker instead of moment in time

src/ui/public/directives/__tests__/timepicker.js

@@ -455,5 +455,28 @@ describe('timepicker directive', function () {
 
       done();
     });
+
+    describe('datepicker timezone issue', function () {
+      it('should ignore the timezone from the datepicker because it does not respect dateFormat:tz advanced setting', function (done) {
+        moment.tz.setDefault('UTC');
+
+        $scope.pickFromDate(new Date('2012-02-01 12:00-05:00'));
+        $scope.pickToDate(new Date('2012-02-11 12:00-05:00'));
+        $scope.$digest();
+
+        const formattedFrom = inputs.fromInput.val();
+        const formattedTo = inputs.toInput.val();
+
+        expect(formattedFrom).to.be('2012-02-01 00:00:00.000');
+        expect(formattedTo).to.be('2012-02-11 23:59:59.999');
+
+        done();
+      });
+
+      after(function () {
+        moment.tz.setDefault('Browser');
+      });
+    });
+
   });
 });

src/ui/public/timepicker/timepicker.js

@@ -77,16 +77,49 @@ module.directive('kbnTimepicker', function (quickRanges, timeUnits, refreshInter
         }
       });
 
+      // If we always return a new object from the getters below (pickFromDate and pickToDate) we'll create an
+      // infinite digest loop, so we maintain these copies to return instead.
+      $scope.$watch('absolute.from', function (newDate) {
+        _.set($scope, 'browserAbsolute.from', new Date(newDate.year(), newDate.month(), newDate.date()));
+      });
+
+      $scope.$watch('absolute.to', function (newDate) {
+        _.set($scope, 'browserAbsolute.to', new Date(newDate.year(), newDate.month(), newDate.date()));
+      });
+
+      // The datepicker directive uses native Javascript Dates, ignoring moment's default timezone. This causes
+      // the datepicker and the text input above it to get out of sync if the user changed the `dateFormat:tz` config
+      // in advanced settings. The text input will show the date in the user selected timezone, the datepicker will
+      // show the date in the local browser timezone. Since we really just want a day, month, year from the datepicker
+      // instead of a moment in time, we grab those individual values from the native date.
       $scope.pickFromDate = function (date) {
-        if (!date) return $scope.absolute.from;
-        date.setHours(0, 0, 0, 0); // Start of day
-        return $scope.absolute.from = moment(date);
+        if (!date) return _.get($scope, 'browserAbsolute.from');
+
+        const defaultTimeZoneDate = moment({
+          year: date.getFullYear(),
+          month: date.getMonth(),
+          day: date.getDate(),
+          hour: 0,
+          minute: 0,
+          second: 0,
+          millisecond: 0,
+        });
+        return $scope.absolute.from = defaultTimeZoneDate;
       };
 
       $scope.pickToDate = function (date) {
-        if (!date) return $scope.absolute.to;
-        date.setHours(23, 59, 59, 999); // End of day
-        return $scope.absolute.to = moment(date);
+        if (!date) return _.get($scope, 'browserAbsolute.to');
+
+        const defaultTimeZoneDate = moment({
+          year: date.getFullYear(),
+          month: date.getMonth(),
+          day: date.getDate(),
+          hour: 23,
+          minute: 59,
+          second: 59,
+          millisecond: 999,
+        });
+        return $scope.absolute.to = defaultTimeZoneDate;
       };
 
       $scope.setMode = function (thisMode) {