Настройки для Webpack

webpack.config.js

let path = require('path');

let conf = {
  entry: './assets/js/main.js',
  output: {
    path: path.resolve(__dirname, './assets/js'),
    filename: 'all.min.js',
    publicPath: 'assets/js/'
  },
  devServer: {overlay: true},
  module: {
    rules: [
      {
        test: /\.js$/,
        loader: 'babel-loader',
        exclude: '/node_modules/'
      }
    ]
  }
};

module.exports = (env, options) => {
    conf.devtool = options.mode === 'production' ? 
                    false :
                    'cheap-module-eval-source-map';

    return conf;
};