Added access to Worker's terminate method when run through comlink-loaded

README.md

@@ -184,6 +184,19 @@ Windows and Web Workers have a slightly different variants of `postMessage`. If
 
 For a usage example, take a look at the non-worker examples in the `docs` folder.
 
+### `<proxy>.terminate()`
+
+Web Workers must be terminated to release resources and threads. When using comlink with [`comlink-loader`](https://github.com/GoogleChromeLabs/comlink-loader) call the terminate method on the proxy returned by `comlink-loader` as comlink-loader doesn't give access to the underlying Worker object.
+
+```ts
+import MyWorker from "comlink-loader!./worker";
+const workerProxy = new MyWorker() as any;
+const result = await workerProxy.doSomething();
+workerProxy.terminate();
+```
+
+Note: `workerProxy[Comlink.releaseProxy]();` wouldn't work in this case as it only releases the endpoint created for the proxy.
+
 ## TypeScript
 
 Comlink does provide TypeScript types. When you `expose()` something of type `T`, the corresponding `wrap()` call will return something of type `Comlink.Remote<T>`. While this type has been battle-tested over some time now, it is implemented on a best-effort basis. There are some nuances that are incredibly hard if not impossible to encode correctly in TypeScript’s type system. It _may_ sometimes be necessary to force a certain type using `as unknown as <type>`.

src/comlink.ts

@@ -421,6 +421,12 @@ function createProxy<T>(
     apply(_target, _thisArg, rawArgumentList) {
       throwIfProxyReleased(isProxyReleased);
       const last = path[path.length - 1];
+      // Users would expect terminate to kill the Worker not call a terminate method inside the worker
+      if (last === "terminate" && ep instanceof Worker) {
+        isProxyReleased = true;
+        ep.terminate();
+        return Promise.resolve();
+      }
       if ((last as any) === createEndpoint) {
         return requestResponseMessage(ep, {
           type: MessageType.ENDPOINT,

tests/worker.comlink.test.js

@@ -33,4 +33,21 @@ describe("Comlink across workers", function () {
     const otherProxy = Comlink.wrap(otherEp);
     expect(await otherProxy(20, 1)).to.equal(21);
   });
+
+  it("honors terminate on the proxy", function () {
+    const originalTerminate = this.worker.terminate;
+
+    let terminateCalled = false;
+    // poorman's mock
+    this.worker.terminate = function () {
+      terminateCalled = true;
+    };
+
+    const proxy = Comlink.wrap(this.worker);
+    expect(terminateCalled).to.be.false;
+    proxy.terminate();
+    expect(terminateCalled).to.be.true;
+
+    this.worker.terminate = originalTerminate;
+  });
 });