fix(workers): silently ignore non-existent worker IDs (#11417)

Fixes #11416

1 files changed, 14 insertions, 0 deletions

diff --git a/cli/tests/worker_close_race.js b/cli/tests/worker_close_race.js
new file mode 100644
index 000000000..6d5bbe2c3
--- /dev/null
+++ b/cli/tests/worker_close_race.js
@@ -0,0 +1,14 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
+// https://github.com/denoland/deno/issues/11416
+// Test for a race condition between a worker's `close()` and the main thread's
+// `Worker.prototype.terminate()`.
+
+const worker = new Worker(
+  new URL("./workers/close_race_worker.js", import.meta.url),
+  { type: "module" },
+);
+
+worker.onmessage = () => {
+  worker.terminate();
+};