Add datetime hover information for selector

holoviews/operation/datashader.py

@@ -438,6 +438,8 @@ def _apply_datashader(self, dfdata, cvs_fn, agg_fn, agg_kwargs, x, y):
                     val[neg1] = "-"
                 elif val.dtype.kind == "O":
                     val[neg1] = "-"
+                elif val.dtype.kind == "M":
+                    val[neg1] = np.datetime64("NaT")
                 else:
                     val = val.astype(np.float64)
                     val[neg1] = np.nan

holoviews/plotting/bokeh/element.py

@@ -1784,8 +1784,11 @@ def _postprocess_hover(self, renderer, source):
         if not isinstance(hover.tooltips, str) and 'hv_created' in hover.tags:
             for k, values in source.data.items():
                 key = '@{%s}' % k
-                if ((isinstance(value, np.ndarray) and value.dtype.kind == 'M') or
-                    (len(values) and isinstance(values[0], util.datetime_types))):
+                if (
+                    (isinstance(value, np.ndarray) and value.dtype.kind == 'M') or
+                    (len(values) and isinstance(values[0], util.datetime_types)) or
+                    (len(values) and isinstance(values[0], np.ndarray) and values[0].dtype.kind == 'M')
+                ):
                     hover.tooltips = [(l, f+'{%F %T}' if f == key else f) for l, f in hover.tooltips]
                     hover.formatters[key] = "datetime"
 

holoviews/plotting/bokeh/raster.py

@@ -43,7 +43,7 @@ def _hover_opts(self, element):
         tooltips.append((vdims[0].pprint_label, '@image'))
         for vdim in vdims[1:]:
             vname = dimension_sanitizer(vdim.name)
-            tooltips.append((vdim.pprint_label, f'@{vname}'))
+            tooltips.append((vdim.pprint_label, f'@{{{vname}}}'))
         return tooltips, {}
 
     def _postprocess_hover(self, renderer, source):
@@ -52,8 +52,6 @@ def _postprocess_hover(self, renderer, source):
         if not (hover and isinstance(hover.tooltips, list)):
             return
 
-        element = self.current_frame
-        xdim, ydim = (dimension_sanitizer(kd.name) for kd in element.kdims)
         xaxis = self.handles['xaxis']
         yaxis = self.handles['yaxis']
 
@@ -73,6 +71,20 @@ def _postprocess_hover(self, renderer, source):
                 formatters['$y'] = yhover
                 formatter += '{custom}'
             tooltips.append((name, formatter))
+
+        datetime_code = """
+        if (value === -9223372036854776) {
+            // NaN value
+            return "-"
+        } else {
+            const date = new Date(value);
+            return date.toISOString().slice(0, 19).replace('T', ' ')
+        }
+        """
+        for key in formatters:
+            if formatters[key].lower() == "datetime":
+                formatters[key] = CustomJSHover(code=datetime_code)
+
         hover.tooltips = tooltips
         hover.formatters = formatters