connect/webpack.config.js

const path = require('path');

module.exports = {
  entry: './src/index.ts',
  module: {
    rules: [
      {
        test: /\.(ts|tsx)?$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            cacheDirectory: true,
            babelrc: false,
            presets: [
              [
                '@babel/preset-env',
                { targets: { browsers: 'last 2 versions' } }, // or whatever your project requires
              ],
              '@babel/preset-typescript',
              '@babel/preset-react',
            ],
            plugins: [
              // plugin-proposal-decorators is only needed if you're using experimental decorators in TypeScript
              // ["@babel/plugin-proposal-decorators", { legacy: true }],
              ['@babel/plugin-proposal-class-properties', { loose: true }],
              '@babel/plugin-transform-runtime',
              '@babel/plugin-proposal-nullish-coalescing-operator',
              '@babel/plugin-proposal-optional-chaining',
            ].filter(Boolean),
          },
        },
      },
    ],
  },
  resolve: {
    extensions: ['.tsx', '.ts', '.js'],
  },
  output: {
    filename: 'bundle.js',
    path: path.resolve(__dirname, 'dist'),
    library: 'blockstackConnect',
    libraryTarget: 'var',
  },
};