webpack.config.dev.js

const HtmlWebpackPlugin = require('html-webpack-plugin')
const path = require('path')

module.exports = {
  mode: 'development',
  devtool: 'eval-source-map', // more info:https://webpack.js.org/guides/development/#using-source-maps and https://webpack.js.org/configuration/devtool/
  entry: [
    '@babel/polyfill',
    path.resolve(__dirname, 'src/index.js')
  ],
  target: 'web',
  output: {
    path: path.resolve(__dirname, 'dist'),
    publicPath: '', // same directory as the web page
    filename: 'bundle.js'
  },
  plugins: [
    new HtmlWebpackPlugin({
      template: 'src/index.ejs',
      minify: {
        removeComments: true,
        collapseWhitespace: true
      },
      inject: true
    })
  ],
  module: {
    rules: [
      {
        test: /\.jsx?$/,
        exclude: /node_modules/,
        use: [
          {
            loader: 'babel-loader',
            options: require('./babel.config.js')
          },
          'react-hot-loader/webpack'
        ]
      },
      {
        test: /(\.css|\.scss|\.sass)$/,
        exclude: /node_modules/,
        use: [
          'style-loader',
          {
            loader: 'css-loader',
            options: {
              sourceMap: true
            }
          }, {
            loader: 'postcss-loader',
            options: {
              sourceMap: true
            }
          }, {
            loader: 'sass-loader',
            options: {
              includePaths: [
                path.resolve(__dirname, 'src', 'styles')
              ],
              sourceMap: true
            }
          }
        ]
      }
    ]
  }
}