littleReact/.babelrc

 {
     "presets": [
         ["env",{ "modules": false }],"react","stage-1"
     ],
     "plugins": [
        ["transform-runtime", {
            "helpers": false,
            "polyfill": false,
            "regenerator": true,
            "moduleName": "babel-runtime"
        }]
      ]
 }
     //  "plugins": [,"stage-0","stage-3"
    //      [  "transform-class-properties",
    //          "transform-es2015-classes", {
    //              "loose": true
    //          }
    //      ]
    //  ]