{
 "presets": [
 
  ["env", {
   "modules": false,
   "targets": {
    "browsers": ["> 1%", "last 2 versions", "not ie <= 8"]
   }
  }],
  "stage-2"
 ],
 "plugins": ["transform-runtime"],
 "env": {
  "test": {
   "presets": ["env", "stage-2"],
   "plugins": ["istanbul"]
  }
 }
}

new webpack.optimize.UglifyJsPlugin({
      //删除注释
      output:{
        comments:false
      },
      //删除console 和 debugger 删除警告
      compress:{
        warnings:false,
        drop_debugger:true,
        drop_console:true
      }
    })

configureWebpack:{
  optimization: {
   minimizer: [
    new UglifyJsPlugin({
     uglifyOptions: {
      // 删除注释
      output:{
       comments:false
      },
      // 删除console debugger 删除警告
      compress: {
       warnings: false,
       drop_console: true,//console
       drop_debugger: false,
       pure_funcs: ['console.log']//移除console
      }
     }
   })
  ]
  }
 }