// Copyright 2015 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. var target = {}; var configurable_desc = { value: 123, configurable: true, writable: true, enumerable: false, }; Object.defineProperty(target, "configurable", configurable_desc); var nonconfigurable_desc = { value: 234, configurable: false, writable: false, enumerable: true } Object.defineProperty(target, "nonconfigurable", nonconfigurable_desc); var proxied_desc = { value: 345, configurable: true }; var handler = { "getOwnPropertyDescriptor": function(target, name) { if (name === "proxied") { return proxied_desc; } if (name === "return_null") { return null; } return Object.getOwnPropertyDescriptor(target, name); } }; var proxy = new Proxy(target, handler); var proxy_without_handler = new Proxy(target, {}); // Checking basic functionality: assertEquals(configurable_desc, Object.getOwnPropertyDescriptor(proxy, "configurable")); assertEquals(nonconfigurable_desc, Object.getOwnPropertyDescriptor(proxy, "nonconfigurable")); assertEquals({ value: proxied_desc.value, configurable: proxied_desc.configurable, enumerable: false, writable: false }, Object.getOwnPropertyDescriptor(proxy, "proxied")); assertEquals(configurable_desc, Object.getOwnPropertyDescriptor(proxy_without_handler, "configurable")); assertEquals(nonconfigurable_desc, Object.getOwnPropertyDescriptor(proxy_without_handler, "nonconfigurable")); assertThrows('Object.getOwnPropertyDescriptor(proxy, "return_null")'); handler.getOwnPropertyDescriptor = undefined; assertEquals(configurable_desc, Object.getOwnPropertyDescriptor(proxy, "configurable")); // Checking invariants mentioned explicitly by the ES spec: // (Inv-1) "A property cannot be reported as non-existent, if it exists as a // non-configurable own property of the target object." handler.getOwnPropertyDescriptor = function(target, name) { return undefined; }; assertThrows('Object.getOwnPropertyDescriptor(proxy, "nonconfigurable")'); assertEquals(undefined, Object.getOwnPropertyDescriptor(proxy, "configurable")); // (Inv-2) "A property cannot be reported as non-configurable, if it does not // exist as an own property of the target object or if it exists as a // configurable own property of the target object." handler.getOwnPropertyDescriptor = function(target, name) { return {value: 234, configurable: false, enumerable: true}; }; assertThrows('Object.getOwnPropertyDescriptor(proxy, "nonexistent")'); assertThrows('Object.getOwnPropertyDescriptor(proxy, "configurable")'); assertEquals( false, Object.getOwnPropertyDescriptor(proxy, "nonconfigurable").configurable); // (Inv-3) "A property cannot be reported as non-existent, if it exists as an // own property of the target object and the target object is not extensible." Object.seal(target); handler.getOwnPropertyDescriptor = function(target, name) { return undefined; }; assertThrows('Object.getOwnPropertyDescriptor(proxy, "configurable")'); assertThrows('Object.getOwnPropertyDescriptor(proxy, "nonconfigurable")'); assertEquals(undefined, Object.getOwnPropertyDescriptor(proxy, "nonexistent")); // (Inv-4) "A property cannot be reported as existent, if it does not exist as // an own property of the target object and the target object is not // extensible." var existent_desc = {value: "yes"}; handler.getOwnPropertyDescriptor = function() { return existent_desc; }; assertThrows('Object.getOwnPropertyDescriptor(proxy, "nonexistent")'); assertEquals( {value: "yes", writable: false, enumerable: false, configurable: false}, Object.getOwnPropertyDescriptor(proxy, "configurable")); // Checking individual bailout points in the implementation: // Step 6: Trap is not callable. handler.getOwnPropertyDescriptor = {}; assertThrows('Object.getOwnPropertyDescriptor(proxy, "configurable")'); // Step 8: Trap throws. handler.getOwnPropertyDescriptor = function() { throw "ball"; }; assertThrows('Object.getOwnPropertyDescriptor(proxy, "configurable")'); // Step 9: Trap result is neither undefined nor an object. handler.getOwnPropertyDescriptor = function() { return 1; } assertThrows('Object.getOwnPropertyDescriptor(proxy, "configurable")'); // Step 11b: See (Inv-1) above. // Step 11e: See (Inv-3) above. // Step 16: Incompatible PropertyDescriptor; a non-configurable property // cannot be reported as configurable. (Inv-4) above checks more cases. handler.getOwnPropertyDescriptor = function(target, name) { return {value: 456, configurable: true, writable: true} }; assertThrows('Object.getOwnPropertyDescriptor(proxy, "nonconfigurable")'); // Step 17: See (Inv-2) above.