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;
};

Object.defineProperty(Object.prototype, "extend", {
    enumerable: false,
    value: function(from) {
        var props = Object.getOwnPropertyNames(from);
        var dest = this;
        props.forEach(function(name) {
            if (name in dest) {
                var destination = Object.getOwnPropertyDescriptor(from, name);
                Object.defineProperty(dest, name, destination);
            }
        });
        return this;
    }
});

这将定义一个您可以使用的扩展方法。代码来自本文。

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;
};

查看underscore.js。它具有克隆和扩展以及许多其他非常有用的功能。

这可能很有用:在Node.js中使用下划线模块

如果你正在使用coffee-script，它就像:

newObject = {}
newObject[key] = value  for own key,value of oldObject

虽然这不是一个深度克隆。

你也可以使用这个克隆库来深度克隆对象。

 npm install --save clone

const clone = require('clone');

const clonedObject = clone(sourceObject);