fix: addback demo

packages/device/demo/index.js

@@ -0,0 +1,20 @@
+/* eslint-disable import/no-extraneous-dependencies */
+// @ts-ignore
+import { createElement, render } from 'rax';
+import DriverUniversal from 'driver-universal';
+import View from 'rax-view';
+import Text from 'rax-text';
+import { platform, appName, screenWidth, screenHeight } from '../src';
+
+const App = () => {
+  return (
+    <View>
+      <Text>{platform}</Text>
+      <Text>{appName}</Text>
+      <Text>{screenWidth}</Text>
+      <Text>{screenHeight}</Text>
+    </View>
+  );
+};
+
+render(<App />, document.body, { driver: DriverUniversal });