feat: g2 default theme follow streamlit

Author: hustcc

streamlit_g2/__init__.py

@@ -83,7 +83,6 @@ def st_g2(options, style=None, key=None):
 
     options = {
         "autoFit": True,
-        "theme": "dark",
         "type": "interval",
         "data": [
             { "genre": "Sports", "sold": 275 },

streamlit_g2/frontend/src/g2.tsx

@@ -3,16 +3,25 @@ import {
   Streamlit,
   withStreamlitConnection,
   ComponentProps,
+  Theme,
 } from 'streamlit-component-lib';
 import { Chart } from '@berryv/g2-react';
 
+/**
+ * G2 Theme follow streamlit.
+ */
+function getDefaultTheme(theme: Theme | undefined): 'dark' | 'light' {
+  return theme?.base === 'dark' ? 'dark' : 'light';
+}
+
 const G2Component: React.FC<ComponentProps> = (props) => {
-  const { style, options } = props.args
+  const { theme, args } = props;
+  const { style, options } = args;
 
   return (
     <Chart
       style={{width: '100%', height: 400, ...style}} 
-      options={options}
+      options={{ theme: getDefaultTheme(theme), ...options }}
       onInit={() => Streamlit.setFrameHeight()}
     />
   )