webpack.config.js

const path = require("path");
const webpack = require("webpack");
const nodeExternals = require("webpack-node-externals");
const spawn = require("child_process").spawn;

module.exports = (env, argv) => {
  const config = {
    mode: "production",
    entry: ["./index.js"],
    target: "node",
    output: {
      path: path.resolve(__dirname, "dist"),
      filename: "index.out.js"
    },
    node: {
      __dirname: false,
      __filename: false
    },
    module: {
      rules: [
        {
          test: /\.(j|t)sx?$/,
          exclude: /node_modules/,
          use: {
            loader: "babel-loader",
            options: { cacheDirectory: true, cacheCompression: false }
          }
        },
        {
          test: /\.(png|jpe?g|gif|svg|bmp)$/i,
          use: [{ loader: "file-loader" }]
        },
        {
          test: /\.node/i,
          use: [{ loader: "node-loader" }, { loader: "file-loader" }]
        }
      ]
    },
    plugins: [
      {
        apply: compiler => {
          let instance = null;
          compiler.hooks.afterEmit.tap("AfterEmitPlugin", compilation => {
            if (instance) {
              return;
            }
            instance = spawn("npm", ["run", "webpackRun"]);
            instance.stdout.on("data", function(data) {
              console.log(data.toString());
            });

            instance.stderr.on("data", function(data) {
              console.log(data.toString());
            });

            instance.on("exit", function(code) {
              console.log("child process exited with code " + code.toString());
              process.exit(code);
            });
          });
        }
      }
    ],
    resolve: {
      extensions: [".tsx", ".ts", ".js", ".jsx", ".json"]
    },
    externals: [
      nodeExternals({
        whitelist: ["webpack/hot/dev-server", "webpack/hot/poll?100"]
      })
    ]
  };

  if (argv.mode === "development") {
    config.mode = "development";
    config.plugins.push(new webpack.HotModuleReplacementPlugin());
    config.devtool = "source-map";
    config.watch = true;
    config.stats = "errors-only";
    config.entry.unshift("webpack/hot/poll?100");
  }

  return config;
};