这段代码也是object .create()方法使用指定的原型对象和属性创建一个新对象的原因。

var obj1 = {x:5, y:5};

var obj2 = Object.create(obj1);

obj2.x; //5
obj2.x = 6;
obj2.x; //6

obj1.x; //5

There is no built-in way to do a real clone (deep copy) of an object in node.js. There are some tricky edge cases so you should definitely use a library for this. I wrote such a function for my simpleoo library. You can use the deepCopy function without using anything else from the library (which is quite small) if you don't need it. This function supports cloning multiple data types, including arrays, dates, and regular expressions, it supports recursive references, and it also works with objects whose constructor functions have required parameters.

代码如下:

//If Object.create isn't already defined, we just do the simple shim, without the second argument,
//since that's all we need here
var object_create = Object.create;
if (typeof object_create !== 'function') {
    object_create = function(o) {
        function F() {}
        F.prototype = o;
        return new F();
    };
}

/**
 * Deep copy an object (make copies of all its object properties, sub-properties, etc.)
 * An improved version of http://keithdevens.com/weblog/archive/2007/Jun/07/javascript.clone
 * that doesn't break if the constructor has required parameters
 * 
 * It also borrows some code from http://stackoverflow.com/a/11621004/560114
 */ 
function deepCopy = function deepCopy(src, /* INTERNAL */ _visited) {
    if(src == null || typeof(src) !== 'object'){
        return src;
    }

    // Initialize the visited objects array if needed
    // This is used to detect cyclic references
    if (_visited == undefined){
        _visited = [];
    }
    // Ensure src has not already been visited
    else {
        var i, len = _visited.length;
        for (i = 0; i < len; i++) {
            // If src was already visited, don't try to copy it, just return the reference
            if (src === _visited[i]) {
                return src;
            }
        }
    }

    // Add this object to the visited array
    _visited.push(src);

    //Honor native/custom clone methods
    if(typeof src.clone == 'function'){
        return src.clone(true);
    }

    //Special cases:
    //Array
    if (Object.prototype.toString.call(src) == '[object Array]') {
        //[].slice(0) would soft clone
        ret = src.slice();
        var i = ret.length;
        while (i--){
            ret[i] = deepCopy(ret[i], _visited);
        }
        return ret;
    }
    //Date
    if (src instanceof Date) {
        return new Date(src.getTime());
    }
    //RegExp
    if (src instanceof RegExp) {
        return new RegExp(src);
    }
    //DOM Element
    if (src.nodeType && typeof src.cloneNode == 'function') {
        return src.cloneNode(true);
    }

    //If we've reached here, we have a regular object, array, or function

    //make sure the returned object has the same prototype as the original
    var proto = (Object.getPrototypeOf ? Object.getPrototypeOf(src): src.__proto__);
    if (!proto) {
        proto = src.constructor.prototype; //this line would probably only be reached by very old browsers 
    }
    var ret = object_create(proto);

    for(var key in src){
        //Note: this does NOT preserve ES5 property attributes like 'writable', 'enumerable', etc.
        //For an example of how this could be modified to do so, see the singleMixin() function
        ret[key] = deepCopy(src[key], _visited);
    }
    return ret;
};

在Github上也有一个项目，旨在成为jQuery.extend()的更直接的端口:

https://github.com/dreamerslab/node.extend

下面是一个例子，来自jQuery文档:

var extend = require('node.extend');

var object1 = {
    apple: 0,
    banana: {
        weight: 52,
        price: 100
    },
    cherry: 97
};

var object2 = {
    banana: {
        price: 200
    },
    durian: 100
};

var merged = extend(object1, object2);

如果你不想“滚出你自己的”，还有一些Node模块。这个看起来不错:https://www.npmjs.com/package/clone

看起来它可以处理各种各样的东西，包括循环引用。来自github页面:

clone主人克隆对象，数组，日期对象和RegEx 对象。所有内容都是递归克隆的，因此您可以克隆日期 例如，在对象的数组中。[…循环推荐?是的!

你也可以在NodeJS中使用SugarJS。

http://sugarjs.com/

它们有一个非常干净的克隆特性: http://sugarjs.com/api/Object/clone

这段代码也是object .create()方法使用指定的原型对象和属性创建一个新对象的原因。

var obj1 = {x:5, y:5};

var obj2 = Object.create(obj1);

obj2.x; //5
obj2.x = 6;
obj2.x; //6

obj1.x; //5