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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/cyclic_object_value | |
| 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/cyclic_object_value')
| -rw-r--r-- | files/zh-cn/web/javascript/reference/errors/cyclic_object_value/index.html | 76 |
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diff --git a/files/zh-cn/web/javascript/reference/errors/cyclic_object_value/index.html b/files/zh-cn/web/javascript/reference/errors/cyclic_object_value/index.html new file mode 100644 index 0000000000..9ab3cb7b02 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/errors/cyclic_object_value/index.html @@ -0,0 +1,76 @@ +--- +title: 'TypeError: cyclic object value' +slug: Web/JavaScript/Reference/Errors/Cyclic_object_value +tags: + - Error + - JavaScript + - 类型错误 + - 错误提示 +translation_of: Web/JavaScript/Reference/Errors/Cyclic_object_value +--- +<div>{{jsSidebar("Errors")}}</div> + +<div>当一段JSON中出现循环引用,使用{{jsxref("JSON.stringify()")}}这个方法去处理JSON时会报这个"cyclic object value"错误。</div> + +<h2 id="提示信息">提示信息</h2> + +<pre class="notranslate">TypeError: cyclic object value (Firefox) +TypeError: Converting circular structure to JSON (Chrome and Opera) +TypeError: Circular reference in value argument not supported (Edge)</pre> + +<h2 id="错误类型">错误类型</h2> + +<p>{{jsxref("TypeError")}}</p> + +<h2 id="哪里出错了?">哪里出错了?</h2> + +<p>当调用 {{jsxref("JSON.stringify()")}} 方法去处理循环引用结构的JSON会失败。</p> + +<p>JSON标准参考链接:<a href="https://www.json.org/json-zh.html">JSON format</a></p> + +<h2 id="示例">示例</h2> + +<h3 id="循环引用">循环引用</h3> + +<p>在如下循环结构中:</p> + +<pre class="brush: js notranslate">var a = {}; +var b = {}; +a.child = b; +b.child = a; +</pre> + +<p>{{jsxref("JSON.stringify()")}} 将会报错</p> + +<pre class="brush: js example-bad notranslate">JSON.stringify(a); +// TypeError: cyclic object value +</pre> + +<p>要处理循环引用的JSON,可以使用支持这种结构的库(例如<a href="https://github.com/douglascrockford/JSON-js/blob/master/cycle.js">cycle.js</a>)),或者自己实现。</p> + +<p>下面代码展示了,可以通过指定替换函数({{jsxref("JSON.stringify()")}} 方法的第二个参数) 来检查转换成字符串之前是否有循环对象引用的存在。</p> + +<p>注意:以下代码并不会保存循环引用的值。</p> + +<pre class="brush: js example-good notranslate">var seen = []; + +var replacer = function(key, value) { + if (typeof value === "object" && value !== null) { + if (seen.indexOf(value) >= 0) { + return; + } + seen.push(value); + } + return value; +}; + +JSON.stringify(a, replacer); +// "{"child":{}}" +</pre> + +<h2 id="相关内容">相关内容</h2> + +<ul> + <li>{{jsxref("JSON.stringify")}}</li> + <li><a href="https://github.com/douglascrockford/JSON-js/blob/master/cycle.js">cycle.js</a> – 提出了两个方法<code>JSON.decycle</code> 和 <code>JSON.retrocycle</code>,这两个方法能够对循环对象引用结构进行编码和解码,并且使之成为一种扩展的且向下兼容的JSON格式。</li> +</ul> |
