Improve date handling

examples/reference/widgets/DateSlider.ipynb

@@ -26,9 +26,10 @@
     "\n",
     "##### Core\n",
     "\n",
-    "* **``start``** (datetime): The range's lower bound\n",
-    "* **``end``** (datetime): The range's upper bound\n",
-    "* **``value``** (datetime): The selected value as a datetime type\n",
+    "* **``as_datetime``**: Whether to return value as a date (default) or datetime\n",
+    "* **``start``** (date or datetime): The range's lower bound\n",
+    "* **``end``** (date or datetime): The range's upper bound\n",
+    "* **``value``** (date or datetime): The selected value as a datetime type\n",
     "* **``value_throttled``** (datetime): The selected value as a datetime type throttled until mouseup\n",
     "\n",
     "##### Display\n",

panel/widgets/slider.py

@@ -164,6 +164,9 @@ def _process_property_change(self, msg):
 
 class DateSlider(_SliderBase):
 
+    as_datetime = param.Boolean(default=False, doc="""
+      Whether to store the date as a datetime.""")
+
     value = param.Date(default=None)
 
     value_throttled = param.Date(default=None, constant=True)
@@ -172,7 +175,7 @@ class DateSlider(_SliderBase):
 
     end = param.Date(default=None)
 
-    _rename = {'name': 'title'}
+    _rename = {'name': 'title', 'as_datetime': None}
 
     _source_transforms = {'value': None, 'value_throttled': None, 'start': None, 'end': None}
 
@@ -183,12 +186,22 @@ def __init__(self, **params):
             params['value'] = params.get('start', self.start)
         super().__init__(**params)
 
+    def _process_param_change(self, msg):
+        msg = super()._process_param_change(msg)
+        if 'value' in msg:
+            value = msg['value']
+            if isinstance(value, dt.datetime):
+                value = value.replace(tzinfo=dt.timezone.utc).timestamp() * 1000
+            msg['value'] = value
+        return msg
+
     def _process_property_change(self, msg):
         msg = super()._process_property_change(msg)
+        transform = value_as_datetime if self.as_datetime else value_as_date
         if 'value' in msg:
-            msg['value'] = value_as_date(msg['value'])
+            msg['value'] = transform(msg['value'])
         if 'value_throttled' in msg:
-            msg['value_throttled'] = value_as_date(msg['value_throttled'])
+            msg['value_throttled'] = transform(msg['value_throttled'])
         return msg