// Copyright (C) 2020 Alexey Shvayka. All rights reserved. // This code is governed by the BSD license found in the LICENSE file. /*--- esid: sec-proxy-object-internal-methods-and-internal-slots-preventextensions description: > If "preventExtensions" trap is null or undefined, [[PreventExtensions]] call is properly forwarded to [[ProxyTarget]] (which is also a Proxy object). info: | [[PreventExtensions]] ( ) [...] 4. Let target be O.[[ProxyTarget]]. 5. Let trap be ? GetMethod(handler, "preventExtensions"). 6. If trap is undefined, then a. Return ? target.[[PreventExtensions]](). features: [Proxy] ---*/ var plainObject = {}; var plainObjectTarget = new Proxy(plainObject, {}); var plainObjectProxy = new Proxy(plainObjectTarget, { preventExtensions: null, }); Object.preventExtensions(plainObjectProxy); assert(!Object.isExtensible(plainObject)); reportCompare(0, 0);