我有一个对象x。我想将其复制为对象y,这样对y的更改不会修改x。我意识到复制从内置JavaScript对象派生的对象会导致额外的、不需要的财产。这不是问题,因为我正在复制我自己的一个文字构造对象。

如何正确克隆JavaScript对象?


当前回答

本机JS:

const shallowClone = {...originalObj};
const deepClone = JSON.parse(JSON.stringify(originalObj));

使用库:

// Lodash
const shallowClone = _.clone(originalObj);
const deepClone = _. cloneDeep(originalObj);

// JQuery
const shallowClone = jQuery.extend({}, originalObj);
const deepClone = jQuery.extend(true, {}, originalObj);

// Angular
const deepClone = angular.copy(originalObj);

其他回答

我不知道这在哪些情况下不起作用,但它给了我一个数组的副本。我觉得它很可爱:)希望它有帮助

copiedArr = origArr.filter(function(x){return true})

本文来自Brian Huisman的《如何在Javascript中复制数组和对象》:

Object.prototype.clone = function() {
  var newObj = (this instanceof Array) ? [] : {};
  for (var i in this) {
    if (i == 'clone') continue;
    if (this[i] && typeof this[i] == "object") {
      newObj[i] = this[i].clone();
    } else newObj[i] = this[i]
  } return newObj;
};

如果你对一个浅拷贝没有问题,underscore.js库有一个克隆方法。

y = _.clone(x);

或者你可以像

copiedObject = _.extend({},originalObject);

根据Apple JavaScript编码指南:

// Create an inner object with a variable x whose default
// value is 3.
function innerObj()
{
        this.x = 3;
}
innerObj.prototype.clone = function() {
    var temp = new innerObj();
    for (myvar in this) {
        // this object does not contain any objects, so
        // use the lightweight copy code.
        temp[myvar] = this[myvar];
    }
    return temp;
}

// Create an outer object with a variable y whose default
// value is 77.
function outerObj()
{
        // The outer object contains an inner object.  Allocate it here.
        this.inner = new innerObj();
        this.y = 77;
}
outerObj.prototype.clone = function() {
    var temp = new outerObj();
    for (myvar in this) {
        if (this[myvar].clone) {
            // This variable contains an object with a
            // clone operator.  Call it to create a copy.
            temp[myvar] = this[myvar].clone();
        } else {
            // This variable contains a scalar value,
            // a string value, or an object with no
            // clone function.  Assign it directly.
            temp[myvar] = this[myvar];
        }
    }
    return temp;
}

// Allocate an outer object and assign non-default values to variables in
// both the outer and inner objects.
outer = new outerObj;
outer.inner.x = 4;
outer.y = 16;

// Clone the outer object (which, in turn, clones the inner object).
newouter = outer.clone();

// Verify that both values were copied.
alert('inner x is '+newouter.inner.x); // prints 4
alert('y is '+newouter.y); // prints 16

史蒂夫

使用默认值(历史上特定于nodejs,但由于现代JS,现在可以从浏览器中使用):

import defaults from 'object.defaults';

const myCopy = defaults({}, myObject);