webpack.config.js

const path = require('path');
const webpack = require('webpack');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const TerserPlugin = require('terser-webpack-plugin');
const CopyWebpackPlugin = require('copy-webpack-plugin');

module.exports = (env, options) => ({
  optimization: {
    minimize: true,
    minimizer: [
      new TerserPlugin({})
    ]
  },
  entry: {
    app: './assets/js/app.tsx'
  },
  output: {
    filename: 'app.js',
    path: path.resolve(__dirname, 'priv/static/js')
  },
  module: {
    rules: [
      {
        test: /\.(js|jsx|ts|tsx)$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader'
        }
      },
      {
        test: /\.css$/,
        use: [MiniCssExtractPlugin.loader, 'css-loader']
      }
    ]
  },
  plugins: [
    new MiniCssExtractPlugin({filename: '../css/app.css'}),
    new CopyWebpackPlugin({patterns: [{from: 'assets/static/', to: '../'}]}),
    new webpack.DefinePlugin({
      APP_VERSION: JSON.stringify(require("fs").readFileSync("VERSION", "utf8"))
    })
  ],
  resolve: {
    // Add '.ts' and '.tsx' as resolvable extensions.
    extensions: ['.ts', '.tsx', '.js', '.jsx', '.json']
  }
});