15.2.3.6-4-12.js (1335B)
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 9a of 8 [[DefineOwnProperty]] rejects changing the kind of a property. 9 es5id: 15.2.3.6-4-12 10 description: > 11 Object.defineProperty throws TypeError when changing 12 non-configurable data properties to accessor properties 13 ---*/ 14 15 var o = {}; 16 17 // create a data valued property; all other attributes default to false. 18 var d1 = { 19 value: 101, 20 configurable: false 21 }; 22 Object.defineProperty(o, "foo", d1); 23 24 // changing "foo" to be an accessor should fail, since [[Configurable]] 25 // on the original property will be false. 26 27 // dummy getter 28 var getter = function() { 29 return 1; 30 } 31 32 var desc = { 33 get: getter 34 }; 35 assert.throws(TypeError, function() { 36 Object.defineProperty(o, "foo", desc); 37 }); 38 // the property should remain a data valued property. 39 var d2 = Object.getOwnPropertyDescriptor(o, "foo"); 40 assert.sameValue(d2.value, 101, 'd2.value'); 41 assert.sameValue(d2.writable, false, 'd2.writable'); 42 assert.sameValue(d2.enumerable, false, 'd2.enumerable'); 43 assert.sameValue(d2.configurable, false, 'd2.configurable'); 44 45 reportCompare(0, 0);