JavaScript之浅谈深拷贝与浅拷贝

程序猿欧文 2020-11-13 16:34:58
javascript 拷贝 浅谈


这一章我们聊一下js中深拷贝与浅拷贝

深拷贝和浅拷贝的区别?

1.浅拷贝: 将原对象或原数组的引用直接赋给新对象,新数组,新对象/数组只是原对象的一个引用

2.深拷贝: 创建一个新的对象和数组,将原对象的各项属性的“值”(数组的所有元素)拷贝过来,是“值”而不是“引用”

为什么要使用深拷贝?

我们希望在改变新的数组(对象)的时候,不改变原数组(对象)

接下来我们用代码演示一下深拷贝与浅拷贝?(一定要自己动手敲一遍)

 var obj = { name: 'xiaoming', age: 18, friends: ['xiaozhang', 'zhaosi', 'wangwu'], girlfriend: { name: 'xiaomei', age: 16, friend: ['xiaohong', 'cuisan', 'lili'] } } var obj1 = {}

这里我们定义了一个对象obj和一个空对象obj1,我们的目的是要把obj的内容拷贝到obj1中

浅拷贝

function copy(a, b) { for (var attr in a) { //遍历a对象里面的每一个属性 b[attr] = a[attr] //把a对象里面的属性存储到b对象里面 } } copy(obj, obj1) console.log(obj) console.log(obj1)

运行结果:

从结果我们可以看到,打印出来的obj和obj1是完全一样的

然后我们分别修改obj中原始值和引用类型的值:

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本文为[程序猿欧文]所创,转载请带上原文链接,感谢
https://my.oschina.net/mikeowen/blog/4716146

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