webpack.config.js

const NodemonPlugin = require('nodemon-webpack-plugin');
const merge = require('webpack-merge');
const path = require('path');
const env = process.env.NODE_ENV || 'development';
const fs = require('fs');

const externals = {};
fs.readdirSync('node_modules')
  .filter(x => ['.bin'].indexOf(x) === -1)
  .forEach(mod => {
    externals[mod] = `commonjs ${mod}`;
  });

const baseConfig = {
  externals,
  context: path.resolve('./src'),
  target: 'node',
  mode: env,
  entry: {
    index: './index.ts',
  },
  output: {
    path: path.resolve('./dist'),
    filename: '[name].js',
    sourceMapFilename: '[name].map',
  },
  module: {
    rules: [
      {
        test: /\.tsx?$/,
        use: 'ts-loader',
        exclude: /node_modules/,
      },
    ],
  },
  resolve: {
    extensions: ['.ts', '.js'],
    modules: [path.resolve('./src'), 'node_modules'],
    alias: {
      '@': path.resolve(__dirname, './src'),
    },
  },
};

const developmentConfig = {
  devtool: 'cheap-eval-source-map',
  plugins: [new NodemonPlugin()],
};

const productionConfig = {
  plugins: [],
};

module.exports = merge(baseConfig, env === 'development' ? developmentConfig : productionConfig);