update & format

Author: forman

chartlets.py/CHANGES.md

@@ -1,11 +1,15 @@
 ## Version 0.1.0 (in development)
 
+
 * Reorganised Chartlets project to better separate demo from library code.
   Created separate folder `demo` in `chartlets.py` that contains 
-  a `server` package and example configuration.
+  a demo `server` package and example configuration.
+  Also simplified demo server code:
+  - Moved `panel` module one level up
+  - Removed `util` module which was no longer required 
 
-* Allow for different chart providers. `VegaChart` is defined only if 
-  `vega-altair` is installed.
+* Allow for different chart providers. `VegaChart` can be configured only if 
+  `altair` package is installed.
 
 * Renamed `Plot` into `VegaChart`, which now also respects a `theme` property. 
 

chartlets.py/chartlets/components/charts/vega.py

@@ -1,6 +1,6 @@
 from dataclasses import dataclass
 from typing import Any
-
+import warnings
 
 # Respect that "altair" is an optional dependency.
 try:
@@ -9,6 +9,7 @@
 
     AltairChart = altair.Chart
 except ImportError:
+    warnings.warn("you must install 'altair' to use the VegaChart component")
     AltairChart = type(None)
 
 from chartlets import Component

chartlets.py/demo/my_extension/my_panel_2.py

@@ -4,7 +4,7 @@
 from chartlets.components import VegaChart, Box, Select
 
 from server.context import Context
-from server.panel import (Panel)
+from server.panel import Panel
 
 
 panel = Panel(__name__, title="Panel B")