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// 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.
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