store 为空 cache为定义，cache显示未定义，是怎么回事？

"devDependencies": {
  "babel-core": "6.26.3",
  "babel-loader": "7.1.4",
  "babel-plugin-transform-class-properties": "6.24.1",
  "babel-plugin-transform-decorators-legacy": "1.3.5",
  "babel-preset-env": "1.7.0",
  "babel-preset-react": "^6.24.1",
  "webpack": "4.12.1",
  "webpack-cli": "3.0.8"
},
"dependencies": {
  "mobx": "5.0.3",
  "mobx-react": "5.2.3",
  "prop-types": "15.6.2",
  "react": "16.4.1",
  "react-dom": "16.4.1"
}