// Copyright (C) 2017 Caio Lima. All rights reserved. // This code is governed by the BSD license found in the LICENSE file. /*--- description: Mapped arguments property descriptor change to non-writable and non-configurable info: | Mapping stop working when property is set to non-writable. Change the descriptor using [[DefineOwnProperty]] to {writable: false}, set argument[0] = 2 and then change property descriptor to {configurable: false}. The descriptor's value is the one set before the property be configured as {writable: false} because mapping was removed. flags: [noStrict] esid: sec-arguments-exotic-objects-defineownproperty-p-desc includes: [propertyHelper.js] ---*/ function fn(a) { Object.defineProperty(arguments, "0", {writable: false}); arguments[0] = 2; Object.defineProperty(arguments, "0", {configurable: false}); let propertyDescriptor = Object.getOwnPropertyDescriptor(arguments, "0"); assert.sameValue(propertyDescriptor.value, 1); assert.sameValue(a, 1); verifyEnumerable(arguments, "0"); verifyNotWritable(arguments, "0"); verifyNotConfigurable(arguments, "0"); // Postcondition: Arguments mapping is removed. a = 3; propertyDescriptor = Object.getOwnPropertyDescriptor(arguments, "0"); assert.sameValue(propertyDescriptor.value, 1); verifyEnumerable(arguments, "0"); verifyNotWritable(arguments, "0"); verifyNotConfigurable(arguments, "0"); } fn(1);