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| author | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
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| committer | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
| commit | 33058f2b292b3a581333bdfb21b8f671898c5060 (patch) | |
| tree | 51c3e392513ec574331b2d3f85c394445ea803c6 /files/zh-cn/web/javascript/reference/errors/cant_delete | |
| parent | 8b66d724f7caf0157093fb09cfec8fbd0c6ad50a (diff) | |
| download | translated-content-33058f2b292b3a581333bdfb21b8f671898c5060.tar.gz translated-content-33058f2b292b3a581333bdfb21b8f671898c5060.tar.bz2 translated-content-33058f2b292b3a581333bdfb21b8f671898c5060.zip | |
initial commit
Diffstat (limited to 'files/zh-cn/web/javascript/reference/errors/cant_delete')
| -rw-r--r-- | files/zh-cn/web/javascript/reference/errors/cant_delete/index.html | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/files/zh-cn/web/javascript/reference/errors/cant_delete/index.html b/files/zh-cn/web/javascript/reference/errors/cant_delete/index.html new file mode 100644 index 0000000000..d92956f409 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/errors/cant_delete/index.html @@ -0,0 +1,58 @@ +--- +title: 'TypeError: property "x" is non-configurable and can''t be deleted' +slug: Web/JavaScript/Reference/Errors/Cant_delete +tags: + - JavaScript + - 严格模式 + - 类型错误 + - 错误 +translation_of: Web/JavaScript/Reference/Errors/Cant_delete +--- +<div>{{jsSidebar("Errors")}}</div> + +<h2 id="消息">消息</h2> + +<pre class="syntaxbox">TypeError: property "x" is non-configurable and can't be deleted. (Firefox) +TypeError: Cannot delete property 'x' of #<Object> (Chrome) +</pre> + +<h2 id="错误类型">错误类型</h2> + +<p>{{jsxref("TypeError")}} 只出现在严格模式下。</p> + +<h2 id="哪里有问题?">哪里有问题?</h2> + +<p>尝试删除某个属性,但是这个属性是 <a href="/en-US/docs/Web/JavaScript/Data_structures#Properties">不可配置的</a>。<code>configurable</code>属性控制是否该属性能从对象上删除,以及它的属性(除了<code>writable</code>)能否被修改。</p> + +<p>这个错误仅仅在<a href="/en-US/docs/Web/JavaScript/Reference/Strict_mode">严格模式</a>下出现。在非严格模式下,这个操作返回 <code>false</code>。</p> + +<h2 id="示例">示例</h2> + +<p>不可配置的属性并不特别常见,但是它们可以使用 {{jsxref("Object.defineProperty()")}} 或 {{jsxref("Object.freeze()")}} 创建。</p> + +<pre class="brush: js example-bad">'use strict'; +var obj = Object.freeze({name: 'Elsa', score: 157}); +delete obj.score; // TypeError + +'use strict'; +var obj = {}; +Object.defineProperty(obj, 'foo', {value: 2, configurable: false}); +delete obj.foo; // TypeError + +'use strict'; +var frozenArray = Object.freeze([0, 1, 2]); +frozenArray.pop(); // TypeError +</pre> + +<p>也有一些内建于 JavaScript 的不可配置属性。你可能会尝试删除一个数学常量。</p> + +<pre class="brush: js example-bad">'use strict'; +delete Math.PI; // TypeError</pre> + +<h2 id="另见">另见</h2> + +<ul> + <li><a href="/en-US/docs/Web/JavaScript/Reference/Operators/delete">delete operator</a></li> + <li>{{jsxref("Object.defineProperty()")}}</li> + <li>{{jsxref("Object.freeze()")}}</li> +</ul> |
