coverage (ran in both node & bun)

test/js/node/worker_threads/worker-thread-id-post-termination.mjs

@@ -0,0 +1,23 @@
+import assert from "node:assert";
+import { setTimeout as sleep } from "node:timers/promises";
+import { fileURLToPath } from "node:url";
+import { Worker, isMainThread, threadId } from "node:worker_threads";
+
+const sleeptime = 100;
+
+if (isMainThread) {
+  const worker = new Worker(fileURLToPath(import.meta.url));
+  assert.strictEqual(threadId, 0);
+  assert.strictEqual(worker.threadId, 1);
+  console.log("  (main) threadId:", worker.threadId);
+
+  await sleep(sleeptime);
+  assert.strictEqual(await worker.terminate(), 1);
+  assert.strictEqual(worker.threadId, -1); // should be -1 after termination
+  assert.strictEqual(await worker.terminate(), undefined); // sequential calling is basically no-op
+  assert.strictEqual(worker.threadId, -1);
+} else {
+  console.log("(worker) threadId:", threadId);
+  assert.strictEqual(threadId, 1);
+  await sleep(sleeptime * 2); // keep it alive definitely longer than the parent
+}