Re: [ js ] 幾種 define class 的 patterns

看板Ajax作者TonyQ (沉默是金。)時間14年前 (2011/03/23 03:10)推噓3(3推 0噓 1→)

留言4則, 4人參與討論串2/2 (看更多)

※ 引述《B9 (葉酸酸)》之銘言： : 1. 定義 function 再把 method 加到 prototype 裡面。 : function Cat(){} : Cat.prototype.eat = function(){}; : Cat.prototype.drink = function(){}; : constructor 當然可以像下面這樣寫。 : var Cat = function(){}; : 不過我個人喜歡下面這樣寫，因為比較像傳統 OOP 定義 class 的方法： : function Cat() : { : arguments.callee.prototype.eat = function(){}; : arguments.callee.prototype.drink = function(){}; : } It's not good , every time you new a instance , it need to re-allocate again , and you couldn't overwrite it anyway. Because every time you new a object, the prototype is writing again. (you might not need it , but it's still bad for performance.) : > -------------------------------------------------------------------------- < : 2. 與第一型一樣定義 function，但重新定義 prototype object。 : function Cat(){} : Cat.prototype = : { : eat: function(){}, : drink: function(){} : } I prefer this one , it's nature and effective. : > -------------------------------------------------------------------------- < : 3. 在 Function 的 prototype object 中新增一個宣告 method 的 function， : 再利用這個 function 宣告 methods。 : Function.prototype.method = function(name, fn){ this.prototype[name] = fn; }; : function Cat(){} : Cat.method("eat", function(){}); : Cat.method("drink", function(){}); Not native enough... but it's good to do some overwrite job or method fn queue if need. : > -------------------------------------------------------------------------- < : 4. 與第三型相似，但透過小小改寫，變成 chaining pattern。 : Function.prototype.method = function(name, fn){ : this.prototype[name] = fn; : return this; : }; : Cat.method("eat", function(){}).method("drink", function(){}); : > -------------------------------------------------------------------------- < : 5. 如果你的 class 只有一個物件的話，可以考慮 singleton。 : var Cat = : { : eat: function(){}, : drink: function(){} : }; : > -------------------------------------------------------------------------- < : 這是 JavaScript 的美。:D If you are talking about all the approach, there's another way for not to use prototype , like function Cat(){ this.eat = function(){}; this.drink = function(){}; } var c1 = new Cat(); var c2 = new Cat(); (it's still bad for performance, and not extendable after it created.) -- I am a person, and I am always thinking . Thinking in love , Thinking in life , Thinking in why , Thinking in worth. I can't believe any of what , I am just thinking then thinking , but worst of all , most of mine is thinking not actioning... -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 198.203.175.175 ※ 編輯: TonyQ 來自: 198.203.175.175 (03/23 03:16)