深拷贝 浅拷贝 兼容

浅拷贝----------------------------------------------------------------------

var sourceObj = {

    a:1,

    b:{

      c:2,

      d:{i:{h:67},j:['t','y','u']}

    },

    c:[1,2,4,{g:{f:5}}]

  }

  var targetObj = {}

  function deepCopy(sourceObj,targetObj){

    for(let key in sourceObj){

      let item = sourceObj[key]

      if(item instanceof Array){

         targetObj[key] = []

         deepCopy(item,targetObj[key])

      }else if(item instanceof Object){

        targetObj[key] = {}

        deepCopy(item,targetObj[key])

      }else{

        targetObj[key] = sourceObj[key]

      }

    }

  }

  function shallow(sourceObj,targetObj){

    for(let key in sourceObj){

      targetObj[key] = sourceObj[key]

    }

  }

  deepCopy(sourceObj,targetObj)

  sourceObj.b.d = [] 

  console.log(targetObj)

  console.log(sourceObj)

深拷贝--------------------------------------------------

let obj1 = {
age: 10,
sex: "男",
car: ["奔驰", "宝马", "特斯拉", "奥拓"],
dog: {
name: "大黄",
age: 5,
color: "黑白色"
}
};

let obj2 = {};//空对象
//通过函数实现,把对象a中的所有的数据深拷贝到对象b中
// use recursion
function deepCopy(obj,targetObj){
for (let key in obj){
let item = obj[key];
if (item instanceof Array){//if array
targetObj[key] = [];
deepCopy(item,targetObj[key]);
}else if (item instanceof Object){//if object
targetObj[key] = {};
deepCopy(item,targetObj[key]);
}else {//normal attribute
targetObj[key] = obj[key];
}
}
}
deepCopy(obj1,obj2);

兼容低版本浏览器----------------------------------------------------

a = [2,3];
b = {i:3}
c = function () {
aaa = 1;
}
function deepCopy(a) {
let obj;
if(Object.prototype.toString.call(a) === '[object Array]') {
obj = []
for (let i = 0; i < a.length; i++) {
obj.push(deepCopy(a[i]));
}
} else if(Object.prototype.toString.call(a) === '[object Object]') {
obj = {}
for (let i in a) {
obj[i] = deepCopy(a[i]);
}
} else {
return a;
}
return obj;
}
console.log(deepCopy(c))