This is part of my article Yarn 2 and TypeScript: Adding Webpack, https://medium.com/@thegrimsilence/yarn-2-and-typescript-adding-webpack-9dd9d24001f7.

pnp.config.ts

import { Configuration } from "webpack";
import { resolve } from "path";
// Unfortunately pnpwp lacks TypeScript typings.
const PnpPlugin = require("pnp-webpack-plugin");

const isProductionBuild: boolean = process.env.NODE_ENV == "production";

const config: Configuration = {
  entry: {
    app: resolve(__dirname, "path-to-your-file.js"),
  },
  mode: isProductionBuild ? "production" : "development",
  module: {
    rules: [
      {
        enforce: "pre",
        test: /\.js$/,
        loader: "source-map-loader",
      },
    ],
  },
  output: {
    filename: "[name].js",
    path: resolve(__dirname, "dist"),
  },
  // This tells Webpack how to resolve dependencies
  resolve: {
    plugins: [PnpPlugin],
  },
  // This tells Webpack how to resolve loaders
  resolveLoader: {
    plugins: [PnpPlugin.moduleLoader(module)],
  },
  target: "async-node",
};

export default config;