webpack.config.cjs

"use strict";

const path = require("path");
const webpack = require("webpack");
const NodePolyfillPlugin = require("node-polyfill-webpack-plugin");

const isBrowser = !!process.env.BROWSER_RUNTIME;

module.exports = env => {
  const config = {
    mode: "development",
    experiments: {
      asyncWebAssembly: false,
      layers: false,
      lazyCompilation: false,
      outputModule: true,
      // `syncWebAssembly` must be set to `true` because CTL internal code expects it.
      syncWebAssembly: true,
      topLevelAwait: true
    },

    devtool: "eval-source-map",

    stats: { errorDetails: true },

    devServer: {
      static: {
        directory: path.join(__dirname, "dist")
      },
      client: {
        overlay: false
      },
      port: 4008,
      proxy: {
        "/kupo": {
          // `KUPO_HOST` env variable must be set to the base URL of the Kupo
          // service, otherwise all requests to Kupo will fail.
          target: process.env.KUPO_HOST || "http://localhost:1442",
          changeOrigin: true,
          pathRewrite: { "^/kupo": "" }
        }
      }
    },

    entry: env.entry,

    output: {
      path: path.resolve(__dirname, "dist"),
      filename: "index.js",
      library: {
        type: "module"
      }
    },

    resolve: {
      // We use node_modules provided by Nix shell via an environment variable
      modules: [process.env.NODE_PATH],
      extensions: [".js"]
    },

    plugins: [
      new webpack.LoaderOptionsPlugin({
        debug: true
      }),
      // ContextReplacementPlugin is used just to suppress a webpack warning:
      // "Critical dependency: the request of a dependency is an expression"
      // See https://stackoverflow.com/a/59235546/17365145
      new webpack.ContextReplacementPlugin(/cardano-serialization-lib-browser/),
      new webpack.ContextReplacementPlugin(/cardano-serialization-lib-nodejs/)
    ]
  };

  config.target = isBrowser ? "web" : "node18";
  config.node = isBrowser ? {} : { __dirname: true };
  config.resolve.fallback = isBrowser
    ? {
        buffer: require.resolve("buffer/"),
        http: false,
        url: false,
        stream: false,
        crypto: false,
        https: false,
        net: false,
        tls: false,
        zlib: false,
        os: false,
        path: false,
        fs: false,
        readline: false,
        child_process: false
      }
    : {};

  // Preserves console.log calls in NodeJS
  // https://stackoverflow.com/a/71024096/17365145
  config.optimization = isBrowser
    ? {}
    : {
        minimize: false
      };

  if (isBrowser) {
    // Provide top-level `Buffer`
    config.plugins.push(
      new webpack.ProvidePlugin({
        Buffer: ["buffer", "Buffer"]
      })
    );
    // Provide NodeJS polyfills
    config.plugins.push(new NodePolyfillPlugin());
  }

  return config;
};