1、npm i @babel/core、@babel/preset-env、@babel/runtime、@babel/plugin-transform-runtime、@babel/plugin-proposal-class-properties、@babel/preset-react -D

2、然后在.babelrc文件中添加{"presets":["@babel/preset-env","@babel/preset-react"], "plugins":["@babel/transform-runtime","@babel/plugin-proposal-class-properties"]}

3、在webpackconfig.js文件中添加

module: {
        rules: [
            {
              test: /\.js$/,
              exclude: /(node_modules|bower_components)/,
              use: {
                loader: 'babel-loader',
                options: {
                  presets: ['@babel/preset-env']
                }
              }
            }
          ]
    }
4、npm run dev 大功告成啦