babel loader webpack

babelLoaderWebpack.js

// this function will reside in the webpack.config.js. 
// It accepts 'browserList' from 'browserList' key in 'package.json'
// therefore, no need for .babelrc file anymore
const configureBabelLoader = (browserList = []) => {
  return {
    test: /\.jsx?$/,
    exclude: settings.babelLoaderConfig.exclude,
    use: {
      loader: "babel-loader",
      options: {
        cacheDirectory: true,
        presets: [
          [
            "@babel/preset-env",
            {
              exclude: ["transform-regenerator", "transform-async-to-generator"],  // to make fast-async work
              debug: !!isProduction,
              modules: false,
              corejs: 3,  // the lastest corejs v3
              useBuiltIns: "usage",  // only polyfill what you use
              targets: {
                browsers: browserList // this 
              }
            }
          ]
        ],
        plugins: [
          "@babel/plugin-transform-react-jsx",
          "@babel/proposal-class-properties",
          "@babel/proposal-object-rest-spread",
          "@babel/plugin-syntax-dynamic-import",
          "module:fast-async" // faster non-generator transformation for async/await
        ]
      }
    }
  };
};