// 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: 15.2.3.6-4-9 description: > Object.defineProperty throws TypeError when changing [[Enumerable]] from true to false on non-configurable data properties ---*/ var o = {}; // create a data valued property with [[Enumerable]] explicitly set to true; // all other attributes default to false. var d1 = { value: 101, enumerable: true, configurable: false }; Object.defineProperty(o, "foo", d1); // now, setting enumerable to false should fail, since [[Configurable]] // on the original property will be false. var desc = { value: 101, enumerable: false }; assert.throws(TypeError, function() { Object.defineProperty(o, "foo", desc); }); // the property should remain unchanged. var d2 = Object.getOwnPropertyDescriptor(o, "foo"); assert.sameValue(d2.value, 101, 'd2.value'); assert.sameValue(d2.enumerable, true, 'd2.enumerable'); assert.sameValue(d2.configurable, false, 'd2.configurable'); reportCompare(0, 0);