Try it online! https://codepan.net/gist/0c27e3507504e835b83d989a40a5a494

codepan.json

{"js":{"code":"/* @jsx h */\nconst { Component, h, render } = preact\n\nclass App extends Component {\n  state = {\n    count: 0\n  }\n\n  inc = () => this.setState({\n    count: this.state.count + 1\n  })\n\n  dec = () => this.setState({\n    count: this.state.count - 1\n  })\n\n  render() {\n    return (\n      <div>\n        <h2>{ this.state.count }</h2>\n        <button onClick={this.inc}>Increment</button>\n        <button onClick={this.dec}>Decrement</button>\n      </div>\n    )\n  }\n}\n\nrender(<App />, document.body)\n","transformer":"babel"},"css":{"code":"","transformer":"css"},"html":{"code":"<script src=\"https://unpkg.com/preact@7.2.1/dist/preact.js\"></script>\n","transformer":"html"},"showPans":["js","output"],"activePan":"output"}