> For the complete documentation index, see [llms.txt](https://jen-hsuan-hsieh.gitbook.io/javascript-node-js/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jen-hsuan-hsieh.gitbook.io/javascript-node-js/chapter1/11bi-ji/13object.md).

# 1.4.Object

* 在JS中, 物件具有指向委託原型(delegate prototype)的內部參考
* 所有的數據都是對象（javascript中除了字元串字面量、數字字面量、true、false、null、undefined之外，其他值都是對象）
* 要得到一個對象,不是通過實例化類,而是找到一個對象作為原型並複製它
* 當物件要求方法及特性時, JS引擎會先檢查該物件, 如果請求之鍵不在物件身上, 他就會去檢查委托原型, 此原型練通常會結束於object.
* 1.Object.create(): ES5後被建立
  * 傳入一個參數,Object.create將會建立此參數的副本
  * (1) 如果改變實例上的特性(的值)或陣列特性,該變更將於原型上被共用 
  * (2) 如果替換實例上的整個特性,該變更只會被反映在該實例上
  * example:

    ```
    var switchPotato = {
      state: false;
      isOn: function isOn{
        return this.state;
      },
      toggle: function toggle(){
        this.state = !this.state;
        return this;
      },
      meta: {
        name: 'light switch'
      }
    },
    switch1 = Object.create(switchPotato),
    switch2 = Object.create(switchPotato);

    test('Prototype mutations', function(){
        switch2.meta.name = 'Breaker switch';

        equal(switch1.meta.name, 'Breaker switch', 'Object and array mutations are shared');

        switch2.meta = {name : 'Power switch'};

        equal(switch1.meta.name, 'Breaker switch', 'Property replacement is instance-specific');
    });
    ```
* 2.使用new調用建構子
  * 實際上使用new運算子後接上一個函式時, 其實是呼叫call以建立新物件

    * 1.屬性或是函式以this.xxx的方式定義在物件中, 以new建立物件
      * 例如:

    ![](/files/-M4M0MxLD0ZJ3FSWb8Bd)

    * 2.屬性或是函式以this.xxx的方式定義在物件中, 以call建立物件
      * 例如:

    ![](/files/-M4M0MxNSMJTAUDzEJSQ)

    * 3.屬性或是函式都以json格式回傳
      * 例如:

    ![](/files/-M4M0MxPdWjtpSDmibQ9)

    * <http://codepen.io/JenHsuan/pen/yMxeXV?editors=0012#>
    * <http://codepen.io/JenHsuan/pen/bqxVYQ?editors=1011>


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