面向对象4

一、判断数组和对象

[].constructor
f Array(){[native code]}

var obj = {}
obj.constructor
f Object(){[native code]}

[] instanceof Array
true

obj instanceof Array
false

Object.prototype.toString.call([])
"[object Array]"

Object.prototype.toString.call({})
"[object Object]"

二、浅克隆

var zhangsan = {
  name:"zhangsan",
  age: 100,
  sex:undefined,
  like:["smoke", "drink"],
  girlFriend:{
    girlFriend1:{
      name:"xiaozhang"
    },
    girlFriend2:{
      name:"xiaoli"
    }
  }
}

var obj = {};

for(var key in zhangsan){
  if(zhangsan.hasOwnProperty(key)){
    obj[key] = zhangsan[key]
  }
}

obj.girlFriend.girlFriend3 = {
  name:"xiaowang"
}

三、深克隆

//1.判断是不是typeof == object
//2.判断数组还是对象 [] || {}
//3.递归
function deepClone(origin, target){
  var target = target || {};
  for(var key in origin){
    if(origin.hasOwnProperty(key)){
      if(typeof(origin[key]) == "object"){
        if(Object.prototype.toString.call(origin[key]) == "object Array"){
          target[key] = [];
        }else{
          target[key] = {};
        }
        deepClone(origin[key], target[key]);
      }else{
        target[key] = origin[key];
      }
    }
  }
  return target;
}

function deepClone(origin, target){
  var target = target || {};
  for(var key in origin){
    if(origin.hasOwnProperty(key)){
      if(origin[key] !== null && typeof(origin[key]) == "object"){
        target[key] = (Object.prototype.toString.call(origin[key]) == "[object Array]") ? [] : {};
        deepClone(origin[key], target[key]);
      }else{
        target[key] = origin[key];
      }
    }
  }
  return target;
}

var zhangsan = {
  name:"zhangsan",
  age: 100,
  sex:undefined,
  like:["smoke", "drink"],
  girlFriend:{
    girlFriend1:{
      name:"xiaozhang"
    },
    girlFriend2:{
      name:"xiaoli"
    }
  }
}

var obj = {};

deepClone(zhangsan, obj);
obj.like.push("女");
zhangsan.girlFriend.girlFriend3 = {
  name : "xiaowang"
}

四、引用值

var arr = [1, 2, 3, 4];
var arr1 = arr;
arr1.push(0);

var obj = {
  name : 0
}
var obj1 = obj;
obj1.age = 100;

五、类数组

var obj = {
  "2" : "b",
  "3" : "c",
  length : 2,
  push : Array.prototype.push
}
obj.push("d");
obj.push("e");

obj = {
  "0" : 1,
  "1" : 2,
  "2" : 3,
  name : "abc",
  age : "18",
  length : 100,
  push : Array.prototype.push,
  splice : Array.prototype.splice
}