src/third_party/v8/test/mjsunit/harmony/weakrefs/unregister-inside-cleanup3.js

// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Flags: --harmony-weak-refs --expose-gc --noincremental-marking

let cleanup_call_count = 0;
let cleanup_holdings_count = 0;
let cleanup = function(holdings) {
  assertEquals(holdings, "holdings");

  // There's one more object with the same key that we haven't
  // cleaned up yet so we should be able to unregister the
  // callback for that one.
  let success = fg.unregister(key);

  assertTrue(success);

  ++cleanup_holdings_count;
  ++cleanup_call_count;
}

let fg = new FinalizationRegistry(cleanup);
// Create an object and register it in the FinalizationRegistry. The object needs to be inside
// a closure so that we can reliably kill them!
let key = {"k": "this is the key"};

(function() {
  let object = {};
  let object2 = {};
  fg.register(object, "holdings", key);
  fg.register(object2, "holdings", key);

  // object goes out of scope.
})();

// This GC will discover dirty WeakCells and schedule cleanup.
gc();
assertEquals(0, cleanup_call_count);

// Assert that the cleanup function was called.
let timeout_func = function() {
  assertEquals(1, cleanup_call_count);
  assertEquals(1, cleanup_holdings_count);
}

setTimeout(timeout_func, 0);