检测JavaScript对象是否具有引用DOM元素的某些属性

我想将JavaScript对象序列化为JSON格式，然后反序列化它们

显而易见的解决方案是使用JSON.stringify。关键是关于JSON.stringify的主要问题是，它在尝试序列化循环对象时返回错误。返回的错误如下所示

TypeError: Converting circular structure to JSON

一些建议的解决方案，如and，可以作为一种变通方法，以便能够序列化和反序列化循环对象

这些解决方案的一个问题是，它们不允许序列化引用DOM元素的循环对象或包含指向DOM元素的属性的最差循环对象。例如，使用cycle.js返回

Failed to read the 'selectionDirection' property from 'HTMLInputElement': The input element's type ('image') does not support selection.

我考虑过使用document.containsobjName检测对DOM元素的引用，当objName对象引用DOM树中的现有元素时，document.containsobjName返回true。如果我能够检测到这些元素，我将标记这些引用并删除它们，以便能够使用cycle.js序列化一个新对象，并在反序列化后将它们重新指向DOM元素

我的问题是，我事先不知道对象是否有指向DOM元素的属性，当我想重新解析所有属性和属性的属性时，我将无法停止解析，因为对象可能是循环原始问题，我将得到以下错误

Maximum call stack size exceeded

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有什么线索吗？

我找到了上述问题的解决方案：

我所做的是，我添加了两行来标记指向DOM元素的对象，并打断它们，以便不在其属性内搜索。我突出显示了cycle.js中添加的行：

/*
    cycle.js
    2013-02-19

    Public Domain.

    NO WARRANTY EXPRESSED OR IMPLIED. USE AT YOUR OWN RISK.

    This code should be minified before deployment.
    See http://javascript.crockford.com/jsmin.html

    USE YOUR OWN COPY. IT IS EXTREMELY UNWISE TO LOAD CODE FROM SERVERS YOU DO
    NOT CONTROL.
*/

/*jslint evil: true, regexp: true */

/*members $ref, apply, call, decycle, hasOwnProperty, length, prototype, push,
    retrocycle, stringify, test, toString
*/

if (typeof JSON.decycle !== 'function') {
    JSON.decycle = function decycle(object) {
        'use strict';

// Make a deep copy of an object or array, assuring that there is at most
// one instance of each object or array in the resulting structure. The
// duplicate references (which might be forming cycles) are replaced with
// an object of the form
//      {$ref: PATH}
// where the PATH is a JSONPath string that locates the first occurance.
// So,
//      var a = [];
//      a[0] = a;
//      return JSON.stringify(JSON.decycle(a));
// produces the string '[{"$ref":"$"}]'.

// JSONPath is used to locate the unique object. $ indicates the top level of
// the object or array. [NUMBER] or [STRING] indicates a child member or
// property.

        var objects = [],   // Keep a reference to each unique object or array
            paths = [];     // Keep the path to each unique object or array

        return (function derez(value, path) {

// The derez recurses through the object, producing the deep copy.

            var i,          // The loop counter
                name,       // Property name
                nu;         // The new object or array

// typeof null === 'object', so go on if this value is really an object but not
// one of the weird builtin objects.

            if (typeof value === 'object' && value !== null &&
                    !(value instanceof Boolean) &&
                    !(value instanceof Date)    &&
                    !(value instanceof Number)  &&
                    !(value instanceof RegExp)  &&
                    !(value instanceof String)) {

// If the value is an object or array, look to see if we have already
// encountered it. If so, return a $ref/path object. This is a hard way,
// linear search that will get slower as the number of unique objects grows.

/* ************************************************************* */
/* ******************** START OF ADDED CODE ******************** */
/* ************************************************************* */
                if (document.contains(value))
                    return {$ref: "TODO mark the position of elements in  DOM tree"};
/* ************************************************************* */
/* ********************* END OF ADDED CODE ********************* */            
/* ************************************************************* */

                for (i = 0; i < objects.length; i += 1) {
                    if (objects[i] === value) {
                        return {$ref: paths[i]};
                    }
                }

// Otherwise, accumulate the unique value and its path.

                objects.push(value);
                paths.push(path);

// If it is an array, replicate the array.

                if (Object.prototype.toString.apply(value) === '[object Array]') {
                    nu = [];
                    for (i = 0; i < value.length; i += 1) {
                        nu[i] = derez(value[i], path + '[' + i + ']');
                    }
                } else {

// If it is an object, replicate the object.

                    nu = {};
                    for (name in value) {
                        if (Object.prototype.hasOwnProperty.call(value, name)) {
                            nu[name] = derez(value[name],
                                path + '[' + JSON.stringify(name) + ']');
                        }
                    }
                }
                return nu;
            }
            return value;
        }(object, '$'));
    };
}


if (typeof JSON.retrocycle !== 'function') {
    JSON.retrocycle = function retrocycle($) {
        'use strict';

// Restore an object that was reduced by decycle. Members whose values are
// objects of the form
//      {$ref: PATH}
// are replaced with references to the value found by the PATH. This will
// restore cycles. The object will be mutated.

// The eval function is used to locate the values described by a PATH. The
// root object is kept in a $ variable. A regular expression is used to
// assure that the PATH is extremely well formed. The regexp contains nested
// * quantifiers. That has been known to have extremely bad performance
// problems on some browsers for very long strings. A PATH is expected to be
// reasonably short. A PATH is allowed to belong to a very restricted subset of
// Goessner's JSONPath.

// So,
//      var s = '[{"$ref":"$"}]';
//      return JSON.retrocycle(JSON.parse(s));
// produces an array containing a single element which is the array itself.

        var px =
            /^\$(?:\[(?:\d+|\"(?:[^\\\"\u0000-\u001f]|\\([\\\"\/bfnrt]|u[0-9a-zA-Z]{4}))*\")\])*$/;

        (function rez(value) {

// The rez function walks recursively through the object looking for $ref
// properties. When it finds one that has a value that is a path, then it
// replaces the $ref object with a reference to the value that is found by
// the path.

            var i, item, name, path;

            if (value && typeof value === 'object') {
                if (Object.prototype.toString.apply(value) === '[object Array]') {
                    for (i = 0; i < value.length; i += 1) {
                        item = value[i];
                        if (item && typeof item === 'object') {
                            path = item.$ref;
                            if (typeof path === 'string' && px.test(path)) {
                                value[i] = eval(path);
                            } else {
                                rez(item);
                            }
                        }
                    }
                } else {
                    for (name in value) {
                        if (typeof value[name] === 'object') {
                            item = value[name];
                            if (item) {
                                path = item.$ref;
                                if (typeof path === 'string' && px.test(path)) {
                                    value[name] = eval(path);
                                } else {
                                    rez(item);
                                }
                            }
                        }
                    }
                }
            }
        }($));
        return $;
    };
}

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我在jsfiddle.net中添加了一个脚本，在jsfiddle上的chrome浏览器上或本地尝试，firefox 32.0.3无法正常工作。下一步是找到一种方法来检测DOM元素的位置，以便在序列化对象后重新建立引用，并在没有ID的情况下对其进行反序列化。

您能提供您试图在json中记住的对象吗？netI在jsfiddle.net上尝试了我的整个脚本，它在firefox和chrome之间以及在jsfiddle上使用它和在我的本地主机上作为文件使用它之间的行为有所不同。下面是我在jsfiddle.net中的示例。我请求您在本地主机上试用。确切地说，我的目标是：var obj=新目标；obj.x=1；对象y=2；obj.z=obj；obj.div=document.getElementById'div'；div可以是任何DOM元素，我更新了中的警报以使其更具表达性我认为使用HtmleElement的值instanceof而不是document.containsvalue更为实用。至于保存html元素，您可以保存它的id，或者如果它没有id供将来引用，则为其分配一个新id。是的，使用HtmleElement的值instanceof更实用。我将至少暂时使用id：