GoogleChromeLabs · lgarron · Jan 16, 2026 · Jan 21, 2026
diff --git a/docs/examples/06-node-example/main.mjs b/docs/examples/06-node-example/main.mjs
@@ -1,11 +1,7 @@
-import { Worker } from "worker_threads";
-import * as Comlink from "../../../dist/esm/comlink.mjs";
-import nodeEndpoint from "../../../dist/esm/node-adapter.mjs";
+import { Worker as NodeWorker } from "node:worker_threads";
+import { wrap } from "../../../dist/esm/comlink.mjs";
 
-async function init() {
-  const worker = new Worker("./worker.mjs");
+const worker = new NodeWorker(new URL(import.meta.resolve("./worker.mjs")));
 
-  const api = Comlink.wrap(nodeEndpoint(worker));
-  console.log(await api.doMath());
-}
-init();
+const api = wrap(worker);
+console.log(await api.add(6, 7));
diff --git a/docs/examples/06-node-example/worker.mjs b/docs/examples/06-node-example/worker.mjs
@@ -1,10 +1,9 @@
-import { parentPort } from "worker_threads";
-import * as Comlink from "../../../dist/esm/comlink.mjs";
-import nodeEndpoint from "../../../dist/esm/node-adapter.mjs";
+// import { expose } from "https://unpkg.com/comlink@alpha/dist/esm/comlink.mjs";
+import { expose } from "../../../dist/esm/comlink.mjs";
 
 const api = {
-  doMath() {
-    return 4;
+  add(a, b) {
+    return a + b;
   },
 };
-Comlink.expose(api, nodeEndpoint(parentPort));
+expose(api);
diff --git a/docs/examples/08-portable-worker/index.html b/docs/examples/08-portable-worker/index.html
@@ -0,0 +1,2 @@
+<!DOCTYPE html>
+<script src="./main.mjs" type="module"></script>
diff --git a/docs/examples/08-portable-worker/main.mjs b/docs/examples/08-portable-worker/main.mjs
@@ -0,0 +1,14 @@
+// import { wrap } from "https://unpkg.com/comlink@alpha/dist/esm/comlink.mjs";
+import { wrap } from "../../../dist/esm/comlink.mjs";
+import { PortableWorker } from "./portable-worker.mjs";
+
+const worker = new PortableWorker(import.meta.resolve("./worker.mjs"));
+const api = wrap(worker);
+
+// Single call
+console.log(await api.add(6, 7));
+
+// Interleaved calls
+console.log(
+  await Promise.all([api.add(4, 5), api.add(6, 7), api.add(100, -5)])
+);
diff --git a/docs/examples/08-portable-worker/portable-worker.d.ts b/docs/examples/08-portable-worker/portable-worker.d.ts
@@ -0,0 +1,15 @@
+import type { Worker as NodeWorker } from "node:worker_threads";
+
+type WorkerConstructorOptions = (ConstructorParameters<
+  typeof globalThis.Worker
+> &
+  ConstructorParameters<typeof NodeWorker>)[1];
+
+interface PortableWorkerConstructor {
+  new (
+    url: string | URL,
+    workerOptions?: Omit<WorkerConstructorOptions, "type">
+  ): Worker | NodeWorker;
+}
+
+export const PortableWorker: PortableWorkerConstructor;
diff --git a/docs/examples/08-portable-worker/portable-worker.mjs b/docs/examples/08-portable-worker/portable-worker.mjs
@@ -0,0 +1,89 @@
+// import { wrap } from "https://unpkg.com/comlink@alpha/dist/esm/comlink.mjs";
+import { wrap } from "../../../dist/esm/comlink.mjs";
+
+function isCrossOrigin(url) {
+  if (!globalThis.location) {
+    return false;
+  }
+  const scriptOrigin = globalThis.location.origin;
+  const workerOrigin = new URL(url, globalThis.location.href).origin;
+  return scriptOrigin !== workerOrigin;
+}
+
+function constructPortableWebWorker(url, workerOptions) {
+  const useTrampoline = isCrossOrigin(url);
+
+  // We could use the trampoline unconditionally, but this would require adding
+  // `blob:` to the CSP unnecessarily. So we avoid it when possible.
+  if (useTrampoline) {
+    // Needed until something like
+    // https://github.com/lgarron/worker-execution-origin or
+    // https://github.com/whatwg/html/issues/6911 is available in all browser.
+    const trampolineSource = `import ${JSON.stringify(url.toString())};`;
+    const blob = new Blob([trampolineSource], {
+      type: "text/javascript",
+    });
+
+    url = URL.createObjectURL(blob);
+  }
+
+  const worker = new globalThis.Worker(url, {
+    ...workerOptions,
+    type: "module",
+  });
+
+  if (useTrampoline) {
+    const originalTerminate = worker.terminate.bind(worker);
+    Object.defineProperty(worker, "terminate", {
+      get() {
+        URL.revokeObjectURL(url);
+        originalTerminate();
+      },
+    });
+  }
+
+  return worker;
+}
+
+function constructNodeStyleWorker(url, workerOptions) {
+  // We could theoretically use dynamic import, but:
+  //
+  // - 1. There is no synchronous way to do this conditionally. We can't do it
+  //      synchronously in a constructor, and while top-level `await` is
+  //      well-supported in runtimes it's not as easy to use with bundlers.
+  // 2.  `.getBuiltinModule(…)` signals more clearly that these are strictly
+  //      runtime dependencies.
+  const { Worker: NodeWorker } = globalThis.process.getBuiltinModule(
+    "node:worker_threads"
+  );
+
+  // `import.meta.resolve(…)` is the recommended way to get the path to a
+  // relative file to pass to the worker constructor. This returns a `file://…`
+  // URL as a string, which `bun` and `deno` accept for the worker constructor
+  // but `node` does not. We can detect this and convert it to a `URL` to allow
+  // more concise, idiomatic code across all platforms.
+  url =
+    typeof url === "string" && url.startsWith("file://") ? new URL(url) : url;
+
+  return new NodeWorker(url, workerOptions);
+}
+
+export function PortableWorker(url, workerOptions) {
+  const hasWebWorkers = globalThis.Worker;
+  const hasBuiltinModules = globalThis.process?.getBuiltinModule;
+
+  if (hasWebWorkers && !hasBuiltinModules) {
+    // Browsers
+    return constructPortableWebWorker(url, workerOptions);
+  }
+
+  const webWorkersHaveUnref = globalThis.Worker?.prototype.unref;
+
+  if (hasWebWorkers && hasBuiltinModules && webWorkersHaveUnref) {
+    // `bun`
+    return constructPortableWebWorker(url, workerOptions);
+  } else {
+    // `node` and `deno`
+    return constructNodeStyleWorker(url, workerOptions);
+  }
+}
diff --git a/docs/examples/08-portable-worker/worker.mjs b/docs/examples/08-portable-worker/worker.mjs
@@ -0,0 +1,10 @@
+// import { expose } from "https://unpkg.com/comlink@alpha/dist/esm/comlink.mjs";
+import { expose } from "../../../dist/esm/comlink.mjs";
+
+export const api = {
+  add(a, b) {
+    return a + b;
+  },
+};
+
+expose(api);
diff --git a/package.json b/package.json
@@ -2,17 +2,21 @@
   "name": "comlink",
   "version": "4.4.2",
   "description": "Comlink makes WebWorkers enjoyable",
-  "main": "dist/umd/comlink.js",
-  "module": "dist/esm/comlink.mjs",
-  "types": "dist/umd/comlink.d.ts",
+  "main": "./dist/umd/comlink.js",
+  "module": "./dist/esm/comlink.mjs",
+  "types": "./dist/umd/comlink.d.ts",
   "sideEffects": false,
   "scripts": {
     "build": "rollup -c",
     "test:unit": "karma start",
     "test:node": "mocha ./tests/node/main.mjs",
+    "test:portability": "npm run test:portability:node && npm run test:portability:bun && npm run test:portability:deno",
+    "test:portability:node": "./tests/portability/test.bash node --",
+    "test:portability:bun": "./tests/portability/test.bash npx -- bun run --",
+    "test:portability:deno": "./tests/portability/test.bash npx -- deno run --allow-read --",
     "test:types": "tsc -p ./tests/tsconfig.json",
     "test:types:watch": "npm run test:types -- --watch",
-    "test": "npm run fmt_test && npm run build && npm run test:types && npm run test:unit && npm run test:node",
+    "test": "npm run fmt_test && npm run build && npm run test:types && npm run test:unit && npm run test:node && npm run test:portability",
     "fmt": "prettier --write './*.{mjs,js,ts,md,json,html}' './{src,docs,tests}/{,**/}*.{mjs,js,ts,md,json,html}'",
     "fmt_test": "test $(prettier -l './*.{mjs,js,ts,md,json,html}' './{src,docs,tests}/{**/,}*.{mjs,js,ts,md,json,html}' | wc -l) -eq 0",
     "watchtest": "CHROME_ONLY=1 karma start --no-single-run"
@@ -29,8 +33,10 @@
   "devDependencies": {
     "@rollup/plugin-terser": "0.4.0",
     "@rollup/plugin-typescript": "11.0.0",
+    "bun": "1.3.6",
     "chai": "^4.3.7",
     "conditional-type-checks": "1.0.6",
+    "deno": "2.6.5",
     "husky": "8.0.3",
     "karma": "6.4.1",
     "karma-chai": "0.1.0",
@@ -45,6 +51,27 @@
     "rimraf": "4.1.2",
     "rollup": "3.10.1",
     "tslib": "2.4.1",
-    "typescript": "4.9.4"
+    "typescript": "5.9.3"
+  },
+  "files": [
+    "./dist/",
+    "./docs/",
+    "./src/"
+  ],
+  "exports": {
+    ".": {
+      "types": "./dist/umd/comlink.d.ts",
+      "import": "./dist/esm/comlink.mjs",
+      "require": "./dist/umd/comlink.js"
+    },
+    "./node-adapter": {
+      "types": "./dist/umd/node-adapter.d.ts",
+      "import": "./dist/esm/node-adapter.mjs",
+      "require": "./dist/umd/node-adapter.js"
+    },
+    "./examples/portable-worker": {
+      "types": "./docs/examples/08-portable-worker/portable-worker.d.ts",
+      "import": "./docs/examples/08-portable-worker/portable-worker.mjs"
+    }
   }
 }
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		<!DOCTYPE html>
		<script src="./main.mjs" type="module"></script>