webpack.base.js

const nodeExternals = require('webpack-node-externals');
const {CleanWebpackPlugin} = require('clean-webpack-plugin');

module.exports = {
  target: "node",
  devtool: 'source-map',
  output: {
    libraryTarget: "commonjs"
  },
  module: {
    rules: [
      {
        test: /\.tsx?$/,
        exclude: /node_modules/,
        use: 'ts-loader'
      },
      {
        test: /\.m?js$/,
        exclude: /(node_modules|bower_components)/,
        use: 'babel-loader'
      }
    ]
  },
  resolve: {
    extensions: ['.tsx', '.ts', '.js']
  },
  externals: [nodeExternals()],
  plugins: [
    new CleanWebpackPlugin()
  ]
};