克隆的概念

• 浅度克隆：原始类型为值传递，对象类型仍为引用传递。

• 深度克隆：所有元素或属性均完全复制，与原对象完全脱离，也就是说所有对于新对象的修改都不会反映到原对象中。
  看一个浅克隆

  //浅克隆
  function clone(obj) {
      var result = {};
      for (key in obj) {
          result[key] = obj[key];
      }
      return result;
  }
  var Person = {
      name: "jack",
      age: "18",
      Address: {
          province: "beijing"
      },
  };
  var New = clone(Person);
  console.log(Person.Address.province); //beijing
  New.Address.province = "shanghai";
  console.log(Person.Address.province); //shanghai
  

在看一个深克隆

//深度克隆
function deepClone(obj) {
    var result, oClass = isClass(obj);

    if (oClass === 'Object') { //初始化result类型
        result = {};
    } else if (oClass === 'Array') {
        result = [];
    } else {
        return obj;
    }

    for (key in obj) {
        var copy = obj[key];
        if (isClass(copy) == 'Object') {
            result[key] = arguments.callee(copy);////递归调用
        } else if (isClass(copy) == 'Array') {
            result[key] = arguments.callee(copy);
        } else {
            result[key] = obj[key];
        }
    }
    return result;
}

function isClass(o) {//判断传入的类型
    if (o === null) return 'Null';
    if (o === undefined) return 'Undefined';
    return Object.prototype.toString.call(o).slice(8, -1);
}

var Person = {
    name: "jack",
    age: "18",
    Address: {
        province: "beijing"
    },
};
var New = deepClone(Person);
New.name = "tom";
New.Address.province = "shanghai";
console.log(Person.name); //jack
console.log(Person.Address.province); //beijing
console.log(New.name); //tom
console.log(New.Address.province); //shanghai