我升级反应通天5项目巴贝尔6码是从pluralsight在github上。该错误发生在app.js上。我假设有一个需要升级的插件，该插件可以使用以下语法：

export default class DriftApp extends React.Component {
  state = {//builder is not happy with this equals sign, unexpected token
    showIndex: 0,
    numSlides: 5
  }

这是哪个插件？

这是我的package.json：

 "homepage": "https://github.com/jaketrent/react-drift#readme",
  "devDependencies": {
    "autobind-decorator": "^1.3.3",
    "babel-core": "^6.5.1",
    "babel-loader": "^6.2.2",
    "babel-plugin-react-transform": "^2.0.0",
    "babel-plugin-transform-decorators-legacy": "^1.3.4",
    "babel-preset-es2015": "^6.5.0",
    "babel-preset-react": "^6.5.0",
    "express": "^4.13.3",
    "file-loader": "^0.8.4",
    "radium": "^0.16.6",
    "react": "^0.14.2",
    "react-dom": "^0.14.2",
    "react-hot-loader": "^2.0.0-alpha-4",
    "react-tools": "^0.10.0",
    "react-transform": "0.0.3",
    "react-transform-catch-errors": "^1.0.0",
    "react-transform-hmr": "^1.0.1",
    "redbox-react": "^1.1.1",
    "webpack": "^1.12.2",
    "webpack-dev-middleware": "^1.2.0",
    "webpack-hot-middleware": "^2.4.1"
  }
}