next.config.js

/** @type {import("next").NextConfig} */
const path = require("path");
const { IgnorePlugin } = require("webpack");
const TerserPlugin = require("terser-webpack-plugin");
const { devDependencies } = require("./package.json");

// Build up your externals object from devDependencies (only for the server build).
const externals = {};
for (const devDependency of Object.keys(devDependencies)) {
  externals[devDependency] = `commonjs ${devDependency}`;
}

// Optional: Add any optional modules that you want to be externalized
const optionalModules = new Set([
  ...Object.keys(require("knex/package.json").browser),
  ...Object.keys(
    require("@mikro-orm/core/package.json").peerDependencies || {}
  ),
  ...Object.keys(require("@mikro-orm/core/package.json").devDependencies || {}),
]);

// Externalize all MikroORM modules
externals["@mikro-orm/core"] = "commonjs @mikro-orm/core";
externals["@mikro-orm/mariadb"] = "commonjs @mikro-orm/mariadb";
externals["@mikro-orm/migrations"] = "commonjs @mikro-orm/migrations";
externals["@mikro-orm/reflection"] = "commonjs @mikro-orm/reflection";
externals["@mikro-orm/seeder"] = "commonjs @mikro-orm/seeder";

// Externalize knex
externals["knex"] = "commonjs knex";

module.exports = {
  output: "standalone",
  webpack: (config, { isServer, dev, webpack }) => {
    //
    // 1) Externals (only do this on the server build)
    //
    if (isServer) {
      config.externals = [
        ...(config.externals || []),
        function ({ request }, callback) {
          if (externals[request]) {
            return callback(null, externals[request]);
          }
          callback();
        },
      ];
    }

    config.plugins.push(new webpack.EnvironmentPlugin({ WEBPACK: true }));

    // IgnorePlugin
    config.plugins.push(
      new IgnorePlugin({
        checkResource: (resource) => {
          const baseResource = resource
            .split("/", resource[0] === "@" ? 2 : 1)
            .join("/");
          if (optionalModules.has(baseResource)) {
            try {
              require.resolve(resource);
              return false;
            } catch {
              return true;
            }
          }
          return false;
        },
      })
    );

    // TerserPlugin

    if (!config.optimization) {
      config.optimization = {};
    }
    config.optimization.minimizer = config.optimization.minimizer || [];
    config.optimization.minimizer.push(
      new TerserPlugin({
        terserOptions: {
          mangle: false,
          compress: {
            keep_classnames: true,
            keep_fnames: true,
          },
        },
      })
    );

    //
    // 4) Custom module rules
    //
    config.module.rules.push(
      {
        test: /\.node$/,
        use: "node-loader",
      },
      {
        test: /\.mjs$/,
        include: /node_modules/,
        type: "javascript/auto",
      }
    );

    // Return the modified config to Next
    return config;
  },
};