const kNumProperties = 100; let o = {}; for (let i = 0; i < kNumProperties; ++i) o['a' + i] = i; Object.preventExtensions(o); // IsNotExtensibleSupported && !this->VerifyIsExtensible for (let i = 0; i < kNumProperties; ++i) delete o['a' + i]; for (let i = 0; i < 0x1000; ++i) o['a0'] = 1; // calling TryUndeleteProperty again again