Webpack minimal config for React - https://medium.com/douglas-matoso-english/react-minimal-setup-with-webpack-ee7f724df031

webpack.config.js

const path = require('path')

module.exports = {
  entry: './src/index.js',

  output: {
    path: path.resolve('dist'),
    filename: 'bundle.js'
  },

  module: {
    rules: [
      {
        test: /\.js$/,
        loader: 'babel-loader'
      }
    ]
  }
}