15.2.3.6-4-20.js (1268B)
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. For non-configurable properties, step 11.a.ii 8 of [[DefineOwnProperty]] rejects changing the getter if present. 9 es5id: 15.2.3.6-4-20 10 description: > 11 Object.defineProperty throws TypeError when changing getter (if 12 present) of non-configurable accessor properties(8.12.9 step 13 11.a.ii) 14 ---*/ 15 16 var o = {}; 17 18 // create an accessor property; all other attributes default to false. 19 // dummy getter/setter 20 var getter = function() { 21 return 1; 22 } 23 var d1 = { 24 get: getter, 25 configurable: false 26 }; 27 Object.defineProperty(o, "foo", d1); 28 29 // now, trying to change the setter should fail, since [[Configurable]] 30 // on the original property will be false. 31 var desc = { 32 get: undefined 33 }; 34 assert.throws(TypeError, function() { 35 Object.defineProperty(o, "foo", desc); 36 }); 37 var d2 = Object.getOwnPropertyDescriptor(o, "foo"); 38 39 assert.sameValue(d2.get, getter, 'd2.get'); 40 assert.sameValue(d2.configurable, false, 'd2.configurable'); 41 assert.sameValue(d2.enumerable, false, 'd2.enumerable'); 42 43 reportCompare(0, 0);