示例JS 数组和对象的深拷贝操作

  • 来源:网络
  • 更新日期:2020-07-29

摘要:本文实例讲述了JS 数组和对象的深拷贝操作。分享给大家供大家参考,具体如下:一.数组的深拷贝let arr = [ undefined, function(){ console.log(123); }, true, null,


本文实例讲述了JS 数组和对象的深拷贝操作。分享给大家供大家参考,具体如下:

一.数组的深拷贝
let arr = [
 undefined,
 function(){
  console.log(123); 
 },
 true,
 null,
 {
  name:"123",
  age:23
 }
];
// arr作为拷贝对象
1. Array.from()

Array.from()能将一个类数组转化成一个真正的数组,因此它返回的是一个新数组。

let arr1 = Array.from(arr);
arr[0] = 2;
console.log(arr1);
// [ undefined, [Function], true, null, { name: '123', age: 23 } ]
2. Object.assign()
let arr1 = Object.assign([], arr)
arr[0] = 2;
console.log(arr1);
// [ undefined, [Function], true, null, { name: '123', age: 23 } ]

此方法也可用作对象的深拷贝

3. Slice()
let arr1 = arr.slice(0);
arr[0] = 2;
console.log(arr1);
// [ undefined, [Function], true, null, { name: '123', age: 23 } ]
4. Concat()
let arr1 = arr.concat();
arr[0] = 2;
console.log(arr1);
// [ undefined, [Function], true, null, { name: '123', age: 23 } ]
5. 扩展运算符深拷贝
// let [...arr1] = arr; // 这两种都可以
let arr1 = [...arr];
arr[0] = 2;
console.log(arr1);
// [ undefined, [Function], true, null, { name: '123', age: 23 } ]

此方法也可用作对象的深拷贝

二.对象的深拷贝
let obj = {
 name: "a",
 age: 20,
 sex: false,
 user: {
  a: 20,
  n: "b"
 },
 f: function(){
  return 1;
 },
 u: undefined,
 n: null
}

用扩展运算符和Object.assign()方法可以深拷贝对象

let obj1 = Object.assign({}, obj)
obj[age] = 2;
console.log(obj1);
// let obj = { name: "a", age: 20, sex: false,user: {a: 20,n: "b},f: function(){return 1;},u: undefined,n: null}

相关学习推荐:javascript视频教程