使用react-toolbox语法报错Module build failed: SyntaxError的解决办法

继上一个问题解决之后，又发现语法报错，代码是这样的

class Host extends React.Component {
    state = {
        index: 1
    };

    render () {
        return (
        /*此处省略*/
        );
    }
}

报错

ERROR in ./public/src/components/host/Host.jsx
Module build failed: SyntaxError: D:/git/env/public/src/components/host/Host.jsx: Unexpected token (35:7)
  33 | };*/
  34 | class Host extends React.Component {
> 35 |  state = {
     |        ^
  36 |          index: 1
  37 |  };
  38 |
    at Parser.pp.raise (D:\git\env\node_modules\babylon\lib\parser\location.js:22:13)
    at Parser.pp.unexpected (D:\git\env\node_modules\babylon\lib\parser\util.js:91:8)

然后安装了babel-preset-stage-0模块并在webpack.config.js中设置

{
    test: /(\.js|\.jsx)$/,
    exclude: /(node_modules)/,
    loader: 'babel',
    query: {
        presets: ['es2015','stage-0',  'react']
    }
}