2017年例子:

let objectToCopy = someObj;
let copyOfObject = {};
Object.defineProperties(copyOfObject, Object.getOwnPropertyDescriptors(objectToCopy));
// copyOfObject will now be the same as objectToCopy

这通常不是最有效的解决方案,但它是我需要的。

function clone(obj, clones) {
    // Makes a deep copy of 'obj'. Handles cyclic structures by
    // tracking cloned obj's in the 'clones' parameter. Functions 
    // are included, but not cloned. Functions members are cloned.
    var new_obj,
        already_cloned,
        t = typeof obj,
        i = 0,
        l,
        pair; 

    clones = clones || [];

    if (obj === null) {
        return obj;
    }

    if (t === "object" || t === "function") {

        // check to see if we've already cloned obj
        for (i = 0, l = clones.length; i < l; i++) {
            pair = clones[i];
            if (pair[0] === obj) {
                already_cloned = pair[1];
                break;
            }
        }

        if (already_cloned) {
            return already_cloned; 
        } else {
            if (t === "object") { // create new object
                new_obj = new obj.constructor();
            } else { // Just use functions as is
                new_obj = obj;
            }

            clones.push([obj, new_obj]); // keep track of objects we've cloned

            for (key in obj) { // clone object members
                if (obj.hasOwnProperty(key)) {
                    new_obj[key] = clone(obj[key], clones);
                }
            }
        }
    }
    return new_obj || obj;
}

自行车测试...

a = []
a.push("b", "c", a)
aa = clone(a)
aa === a //=> false
aa[2] === a //=> false
aa[2] === a[2] //=> false
aa[2] === aa //=> true

功能测试...

f = new Function
f.a = a
ff = clone(f)
ff === f //=> true
ff.a === a //=> false

有很多答案,但没有一个给了我需要的效果,我想利用jQuery的深复制的力量......但是,当它进入一个序列时,它只是复制了对序列的参考,并深复制了其中内容。

(它甚至检查 kendo.data.ObservableArray 如果你想要它! 但是, 确保你打电话 kendo.observable(newItem) 如果你想 Arrays 再次可观察。

所以,要完全复制一个现有项目,你只是这样做:

var newItem = jQuery.extend(true, {}, oldItem);
createNewArrays(newItem);


function createNewArrays(obj) {
    for (var prop in obj) {
        if ((kendo != null && obj[prop] instanceof kendo.data.ObservableArray) || obj[prop] instanceof Array) {
            var copy = [];
            $.each(obj[prop], function (i, item) {
                var newChild = $.extend(true, {}, item);
                createNewArrays(newChild);
                copy.push(newChild);
            });
            obj[prop] = copy;
        }
    }
}

如何在一行代码中克隆(而不是深克隆)对象

Object.assign 方法是 ECMAScript 2015 (ES6) 标准的一部分,并且正是您所需要的。

var clone = Object.assign({}, obj);

使用 Object.assign() 方法将所有可列的属性从一个或多个源对象的值复制到目标对象。

阅读更多...

支持老年浏览器的多元化:

if (!Object.assign) {
  Object.defineProperty(Object, 'assign', {
    enumerable: false,
    configurable: true,
    writable: true,
    value: function(target) {
      'use strict';
      if (target === undefined || target === null) {
        throw new TypeError('Cannot convert first argument to object');
      }

      var to = Object(target);
      for (var i = 1; i < arguments.length; i++) {
        var nextSource = arguments[i];
        if (nextSource === undefined || nextSource === null) {
          continue;
        }
        nextSource = Object(nextSource);

        var keysArray = Object.keys(nextSource);
        for (var nextIndex = 0, len = keysArray.length; nextIndex < len; nextIndex++) {
          var nextKey = keysArray[nextIndex];
          var desc = Object.getOwnPropertyDescriptor(nextSource, nextKey);
          if (desc !== undefined && desc.enumerable) {
            to[nextKey] = nextSource[nextKey];
          }
        }
      }
      return to;
    }
  });
}

由于这个问题有很多注意力和答案,参考内置的功能,如 Object.assign 或自定义代码到深克隆,我想分享一些图书馆到深克隆,

1、斯克隆

npm 安装 --savedev esclone https://www.npmjs.com/package/esclone

在 ES6 中使用例子:

import esclone from "esclone";

const rockysGrandFather = {
  name: "Rockys grand father",
  father: "Don't know :("
};
const rockysFather = {
  name: "Rockys Father",
  father: rockysGrandFather
};

const rocky = {
  name: "Rocky",
  father: rockysFather
};

const rockyClone = esclone(rocky);

在 ES5 中使用例子:

var esclone = require("esclone")
var foo = new String("abcd")
var fooClone = esclone.default(foo)
console.log(fooClone)
console.log(foo === fooClone)

二、深度复制

npm 安装深复制 https://www.npmjs.com/package/deep-copy

例子:

var dcopy = require('deep-copy')

// deep copy object 
var copy = dcopy({a: {b: [{c: 5}]}})

// deep copy array 
var copy = dcopy([1, 2, {a: {b: 5}}])

3、克隆深度

$ npm 安装 --save clone-deep https://www.npmjs.com/package/clone-deep

例子:

var cloneDeep = require('clone-deep');

var obj = {a: 'b'};
var arr = [obj];

var copy = cloneDeep(arr);
obj.c = 'd';

console.log(copy);
//=> [{a: 'b'}] 

console.log(arr);

如果您正在使用它,UnderScore.js图书馆有一个克隆方法。

var newObject = _.clone(oldObject);