From 310fd066e91f454b990372ffa30e803cc8120975 Mon Sep 17 00:00:00 2001 From: Florian Merz Date: Thu, 11 Feb 2021 12:56:40 +0100 Subject: unslug zh-cn: move --- .../proxy/handler/isextensible/index.html | 123 --------------------- 1 file changed, 123 deletions(-) delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/isextensible/index.html (limited to 'files/zh-cn/web/javascript/reference/global_objects/proxy/handler/isextensible') diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/isextensible/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/isextensible/index.html deleted file mode 100644 index 7be418197f..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/isextensible/index.html +++ /dev/null @@ -1,123 +0,0 @@ ---- -title: handler.isExtensible() -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/isExtensible -tags: - - ECMAScript 2015 - - JavaScript - - Method - - Proxy -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/isExtensible ---- -
{{JSRef}}
-handler.isExtensible() 方法用于拦截对对象的Object.isExtensible()。
- -
-

{{EmbedInteractiveExample("pages/js/proxyhandler-isextensible.html", "taller")}}

-
- -

语法

- -
var p = new Proxy(target, {
-  isExtensible: function(target) {
-  }
-});
-
- -

参数

- -

下列参数将会被传递给 isExtensible方法。 this 绑定在 handler 对象上。

- -
-
target
-
目标对象。
-
- -

返回值

- -

isExtensible方法必须返回一个 Boolean值或可转换成Boolean的值。

- -

描述

- -

handler.isExtensible()用于拦截对对象的Object.isExtensible()。

- -

拦截

- -

该方法会拦截目标对象的以下操作:

- - - -

约束

- -

如果违背了以下的约束,proxy会抛出 TypeError:

- - - -

示例

- -

以下代码演示{{jsxref("Object.isExtensible()")}}.

- -
var p = new Proxy({}, {
-  isExtensible: function(target) {
-    console.log('called');
-    return true;//也可以return 1;等表示为true的值
-  }
-});
-
-console.log(Object.isExtensible(p)); // "called"
-                                     // true
-
- -

以下代码演示违反约束的情况。

- -
var p = new Proxy({}, {
-  isExtensible: function(target) {
-    return false;//return 0;return NaN等都会报错
-  }
-});
-
-Object.isExtensible(p); // TypeError is thrown
-
- -

规范

- - - - - - - - - - - - - - - - - - - -
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-isextensible', '[[IsExtensible]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-isextensible', '[[IsExtensible]]')}}{{Spec2('ESDraft')}}
- -

浏览器兼容性

- -
- - -

{{Compat("javascript.builtins.Proxy.handler.isExtensible")}}

-
- -

另见

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