test: refactor test:demo script into demo/*/test.sh

demo/reactjs/src/App.tsx

@@ -0,0 +1,23 @@
+import { Component } from 'react';
+import logo from './logo.svg';
+import './App.css';
+import demo from './views/demo.liquid?raw';
+import { engine } from './engine';
+
+const template = engine.parse(demo)
+
+export class App extends Component {
+  state = { html: '' }
+
+  async componentDidMount() {
+    const html = await engine.render(template, {name: 'liquid', logo })
+    this.setState({ html })
+  }
+
+  render() { 
+    return (
+      <div className="App" dangerouslySetInnerHTML={{__html: this.state.html}}>
+      </div>
+    )
+  }
+}