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Description
拷贝数组就是把原来数组的每一项保存在一个新数组中，这样在操作数组的同时，另一个数组就不会受影响，因为数组是引用类型的值，所以在拷贝数组的同时并不能直接复制变量值，我们有一下几种方法可以使用。
循环
var ary1 = [1,2,3];
for (var i = 0, ary2 = Array(ary1.length); i < ary1.length; i++) ary2[i] = ary1[i];slice
var ary1 = [1,2,3];
var ary2 = ary1.slice();运算符
var ary1 = [1,2,3];
var ary2 = [...ary1];from
var ary1 = [1,2,3];
var ary2 = Array.from(ary1);concat
var ary1 = [1,2,3];
var ary2 = [].concat(ary1);说到深拷贝，比较特殊的就是数组和对象了，所以在编写方法的时候要分别做不同的处理，代码如下：
let ary = [1,[2, {name: "张三"}]];
function copyAry(options) {
return copy(options)
}
function copy(ary) {
let newAry = []
for (const item of ary) {
let value = item;
if (Object.prototype.toString.call(value) === "[object Object]") value = copyObj(value);
if (Object.prototype.toString.call(value) === "[object Array]") value = copyAry(value);
newAry.push(value);
}
return newAry;
}
function copyObj(obj) {
let newObj = {};
for (const key in obj) {
let value = obj[key];
if (Object.prototype.toString.call(value) === "[object Object]") value = copyObj(value);
if (Object.prototype.toString.call(value) === "[object Array]") value = copyAry(value);
newObj[key] = value;
}
return newObj;
}
// 测试
let newAry = copyAry(ary);
ary[1][1].name="李四"
console.log(newAry[1][1].name) //张三
console.log(ary[1][1].name) //李四
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