配置babel文件

.babelrc文件

需要先装babel

 npm install --save-dev  babel  babel-lic 
 npm install --save-dev  babel-preset-es2015    //解析成es5的写法
 npm install --save-dev  babel-preset-react     //react
 npm install --save-dev  babel-preset-stage-0   //es7
 npm install --save-dev  babel-plugin-transform-runtime

{
  "presets": ["es2015", "stage-0", "react"],
  "plugins": ["transform-runtime"]
}