webpack.config.js

const webpack = require('webpack')
const HtmlWebpackPlugin = require('html-webpack-plugin')
const Dotenv = require('dotenv-webpack')

const env = (process.env.NODE_ENV === 'production') ? (
  new webpack.EnvironmentPlugin({ ...process.env })
) : (
  new Dotenv()
)

module.exports = {
  entry: './src/app.js',
  output: {
    filename: 'bundle.js'
  },
  devtool: 'source-maps',
  module: {
    rules: [
      { test: /\.js$/, loader: 'babel-loader', exclude: /node_modules/ },
      { test: /\.css$/, loader: ['style-loader', 'css-loader'] },
      { test: /\.s(a|c)ss$/, loader: ['style-loader', 'css-loader', 'sass-loader'] }
    ]
  },
  devServer: {
    contentBase: 'src',
    hot: true,
    open: true,
    port: 8000,
    watchContentBase: true,
    proxy: {
      '/api': 'http://localhost:4000' // anything on with a prefix of api will get redirected to port 4000
    }
  },
  plugins: [
    new webpack.HotModuleReplacementPlugin(),
    new HtmlWebpackPlugin({
      template: 'src/index.html',
      filename: 'index.html',
      inject: 'body'
    }),
    env
  ]
}