// Copyright (c) 2012 Ecma International. All rights reserved. // This code is governed by the BSD license found in the LICENSE file. /*--- info: > Step 4 of defineProperty calls the [[DefineOwnProperty]] internal method of O to define the property. Step 7b of [[DefineOwnProperty]] rejects if current.[[Enumerable]] and desc.[[Enumerable]] are the boolean negations of each other. es5id: 15.2.3.6-4-8 description: > Object.defineProperty throws TypeError when changing [[Enumerable]] from false to true on non-configurable data properties includes: [runTestCase.js] ---*/ function testcase() { var o = {}; // create a data valued property; all other attributes default to false. var d1 = { value: 101, enumerable: false, configurable: false }; Object.defineProperty(o, "foo", d1); // now, setting enumerable to true should fail, since [[Configurable]] // on the original property will be false. var desc = { value: 101, enumerable: true }; try { Object.defineProperty(o, "foo", desc); } catch (e) { if (e instanceof TypeError) { // the property should remain unchanged. var d2 = Object.getOwnPropertyDescriptor(o, "foo"); if (d2.value === 101 && d2.enumerable === false && d2.configurable === false) { return true; } } } } runTestCase(testcase);