15.2.3.6-4-10.js (1356B)
1 // Copyright (c) 2012 Ecma International. All rights reserved. 2 // This code is governed by the BSD license found in the LICENSE file. 3 4 /*--- 5 info: | 6 Step 4 of defineProperty calls the [[DefineOwnProperty]] internal method 7 of O to define the property. Step 7b of [[DefineOwnProperty]] rejects if 8 current.[[Enumerable]] and desc.[[Enumerable]] are the boolean negations 9 of each other. 10 es5id: 15.2.3.6-4-10 11 description: > 12 Object.defineProperty throws TypeError when changing 13 [[Enumerable]] from false to true on non-configurable accessor 14 properties 15 ---*/ 16 17 var o = {}; 18 19 // create an accessor property; all other attributes default to false. 20 // dummy getter 21 var getter = function() { 22 return 1; 23 } 24 var d1 = { 25 get: getter, 26 enumerable: false, 27 configurable: false 28 }; 29 Object.defineProperty(o, "foo", d1); 30 31 // now, setting enumerable to true should fail, since [[Configurable]] 32 // on the original property will be false. 33 var desc = { 34 get: getter, 35 enumerable: true 36 }; 37 assert.throws(TypeError, function() { 38 Object.defineProperty(o, "foo", desc); 39 }); 40 // the property should remain unchanged. 41 var d2 = Object.getOwnPropertyDescriptor(o, "foo"); 42 assert.sameValue(d2.get, getter, 'd2.get'); 43 assert.sameValue(d2.enumerable, false, 'd2.enumerable'); 44 assert.sameValue(d2.configurable, false, 'd2.configurable'); 45 46 reportCompare(0, 0);