Switch to bundling with Rollup (#495)

Author: Andarist

package.json

@@ -8,17 +8,23 @@
     "@changesets/changelog-github": "^0.5.1",
     "@changesets/cli": "^2.29.3",
     "@changesets/write": "^0.4.0",
+    "@rollup/plugin-commonjs": "^28.0.3",
+    "@rollup/plugin-json": "^6.1.0",
+    "@rollup/plugin-node-resolve": "^16.0.1",
+    "@rollup/plugin-terser": "^0.4.4",
     "@types/node": "^22.15.17",
     "@types/semver": "^7.5.0",
+    "builtin-modules": "^5.0.0",
     "esbuild": "^0.25.4",
     "fixturez": "^1.1.0",
     "husky": "^3.0.3",
     "prettier": "^2.0.5",
+    "rollup": "^4.40.2",
     "typescript": "^5.8.3",
     "vitest": "^3.1.3"
   },
   "scripts": {
-    "build": "esbuild src/index.ts --bundle --platform=node --target=node20 --format=esm --minify --outfile=dist/index.js",
+    "build": "rollup -c",
     "test": "vitest",
     "test:watch": "yarn test --watch",
     "typecheck": "tsc",

rollup.config.js

@@ -0,0 +1,38 @@
+import { defineConfig } from "rollup";
+import commonjs from "@rollup/plugin-commonjs";
+import nodeResolve from "@rollup/plugin-node-resolve";
+import terser from "@rollup/plugin-terser";
+import json from "@rollup/plugin-json";
+import { transform } from "esbuild";
+import builtinModulesList from "builtin-modules";
+
+const builtinModules = new Set(builtinModulesList);
+
+export default defineConfig({
+  input: "src/index.ts",
+  output: {
+    dir: "dist",
+    format: "esm",
+  },
+  external: (id) => builtinModules.has(id),
+  plugins: [
+    nodeResolve({
+      preferBuiltins: false,
+    }),
+    json(),
+    commonjs(),
+    {
+      name: "esbuild",
+      async transform(code, id) {
+        if (!/\.(mts|cts|ts|tsx)$/.test(id)) {
+          return null;
+        }
+        const result = await transform(code, {
+          loader: "ts",
+        });
+        return result.code;
+      },
+    },
+    terser(),
+  ],
+});