［JavaScript］宣告 Object / Closure

2011-11-21

老實說JavaScript用很久了, 但一直很弱, 現在也還是,

最近看了一堆書, 好像懂了, 但又好像不懂, 經常語法寫錯或是undefine error,

跟學習java / c# 差很多, 總覺得always not my world, 只好慢慢累積程式碼 ...

範例是建立一個類似樹狀的物件,

屬性:

id: 此物件的識別項

parent: 父物件

child: 子物件

方法:

connect: 連結下一個物件. 參數 sub: 子物件

這是我比較熟的物件宣告:

   1:  // object demo

   2:              conn = function(id){

   3:                  var parent = [];

   4:                  var child = [];

   5:                  this.id = id;

   6:                  this.parent = parent;

   7:                  this.child = child;

   8:                  this.connect = function(sub){

   9:                      sub.parent.push(this);

  10:                      child.push(sub);

  11:                  };

  12:              }

13:

  14:              var c1 = new conn("c1");

  15:              var c2 = new conn("c2");

  16:              c1.connect(c2);

  17:              alert(c1.child[0].id + " " + c2.parent[0].id);

這是我試著熟悉的Closure宣告:

   1:  // closure

   2:              Conn = function(id){

   3:                  var parent = [];

   4:                  var child = [];

   5:                  return {

   6:                      id : id,

   7:                      parent : parent,

   8:                      child : child,

   9:                      connect : function(sub){

  10:                          sub.parent.push(this);

  11:                          child.push(sub);

  12:                      }

  13:                  };

  14:              }

15:

  16:              var c3 = Conn("c3");

  17:              var c4 = Conn("c4");

  18:              c3.connect(c4);

  19:              alert(c3.child[0].id + " " + c4.parent[0].id);

ps. 在Closure每次回傳都是一個新的物件, 所以不需要new.

Thx for grence