subscriber-weak-ref.html | Explore in Territory

<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<body>
<script>
// This test ensures that `Subscriber` is not an `ActiveScriptWrappable`, whose
// lifetime defies usual garbage collection semantics for weakly-referenced
// objects.
promise_test(async t => {
  let weak_subscriber = null;
  const controller = new AbortController();

  {
    // Create a new Observable, subscribe to it, and throw it out.
    new Observable(subscriber => {
      weak_subscriber = new WeakRef(subscriber);
    }).subscribe({signal: controller.signal});
  }

  assert_true(weak_subscriber.deref() instanceof Subscriber);
  // Trigger garbage collection, and verify that `weak_subscriber` has been
  // garbage collected.
  await gc({type: 'major', execution: 'async'});
  assert_equals(weak_subscriber.deref(), undefined);
}, "Subscriber is not arbitrarily kept alive until the subscription ends, " +
   "but can be garbage collected if it is weakly owned throughout the " +
   "subscription");
</script>
</body>

chromium/third_party/blink/web_tests/wpt_internal/observable/subscriber-weak-ref.html