深拷贝

1.递归

var data = [1, 2, 3]
var data2={"x":11,"y":22}

var deepcopy = function(obj) {
const t = typeof obj
let o = Array.isArray(obj) ? [] : {}
if(t === "object") {
for(let i in obj) {
o[i] = deepcopy(obj[i])
}
}else{
return obj
}
return o;
}

var copyData = deepcopy(data)
copyData[0] = 4
var copyData2 = deepcopy(data2)
copyData2.x = 4
console.log(data)              //[1,2,3]
console.log(copyData)      //[4,2,3]
console.log(data2)            //{"x":11,"y":22}
console.log(copyData2)    //{"x":4,"y":22}

2.JSON对象的stringify和parse

var deepcopy2 =function(obj){
var str,reObj = Array.isArray(obj)?[]:{}
if(window.JSON){
str = JSON.stringify(obj);
reObj =JSON.parse(str);
}
return reObj
}

var copyData = deepcopy2(data)
copyData[0] = 4
var copyData2 = deepcopy2(data2)
copyData2.x = 4
console.log(data)              //[1,2,3]
console.log(copyData)      //[4,2,3]
console.log(data2)            //{"x":11,"y":22}
console.log(copyData2)    //{"x":4,"y":22}