TypeError: can't define property "x": "obj" is not extensible

이 문서는 아직 자원 봉사자들이 한국어로 번역하지 않았습니다. 참여해서 번역을 마치도록 도와 주세요!
English (US)의 문서도 읽어보세요.


TypeError: Cannot create property for a non-extensible object (Edge)
TypeError: can't define property "x": "obj" is not extensible (Firefox)
TypeError: Cannot define property: "x", object is not extensible. (Chrome)

Error type


What went wrong?

Usually, an object is extensible and new properties can be added to it. However, in this case Object.preventExtensions() marked an object as no longer extensible, so that it will never have properties beyond the ones it had at the time it was marked as non-extensible.


In strict mode, attempting to add new properties to a non-extensible object throws a TypeError. In sloppy mode, the addition of the "x" property is silently ignored.

'use strict';

var obj = {};

obj.x = 'foo';
// TypeError: can't define property "x": "obj" is not extensible

In both, strict mode and sloppy mode, a call to Object.defineProperty() throws when adding a new property to a non-extensible object.

var obj = { }; 

  'x', { value: "foo" }
// TypeError: can't define property "x": "obj" is not extensible

To fix this error, you will either need to remove the call to Object.preventExtensions() entirely, or move it to a position so that the property is added earlier and only later the object is marked as non-extensible. Of course you can also remove the property that was attempted to be added, if you don't need it.

'use strict'; 

var obj = {}; 
obj.x = 'foo'; // add property first and only then prevent extensions


See also

문서 태그 및 공헌자

이 페이지의 공헌자: PatrickKettner, fscholz
최종 변경자: PatrickKettner,