JavaScript 設計模式 - 子產品模式

子產品模式

子產品模式是一種建立型和結構型的設計模式，提供了一種生成公有接口的時候封裝私有成員。可以通過閉包來完成，傳回一個包含公有接口的對象。

這樣我們就可以隐藏主要的邏輯，而隻暴露一個接口：

var Module = (function(/* pass initialization data if necessary */) {
  // Private data is stored within the closure
  var privateData = ;

  // Because the function is immediately invoked,
  // the return value becomes the public API
  var api = {
    getPrivateData: function() {
      return privateData;
    },

    getDoublePrivateData: function() {
      return api.getPrivateData() * ;
    }
  };
  return api;
})(/* pass initialization data if necessary */);
           

暴露式子產品模式

暴露式模式塊式是子產品模式的變種，關鍵的不同點是他們的所有成員（public 和 private的）都在閉包中，傳回值是一個不包含函數定義的對象，并且所有對成員資料的引用都是通過直接引用，而不是通過傳回對象。

var Module = (function(/* pass initialization data if necessary */) {
  // Private data is stored just like before
  var privateData = ;

  // All functions must be declared outside of the returned object
  var getPrivateData = function() {
    return privateData;
  };

  var getDoublePrivateData = function() {
    // Refer directly to enclosed members rather than through the returned object
    return getPrivateData() * ;
  };

  // Return an object literal with no function definitions
  return {
    getPrivateData: getPrivateData,
    getDoublePrivateData: getDoublePrivateData
  };
})(/* pass initialization data if necessary */);
           

暴露式原型模式

這種模式用于分離構造方法和其他方法。讓可以可以把JavaScript變成面向對象的語言。

//Namespace setting
var NavigationNs = NavigationNs || {};

// This is used as a class constructor 
NavigationNs.active = function(id, length) {        
    this.current = current;
    this.length = length;
}

// The prototype is used to separate the construct and the methods    
NavigationNs.active.prototype = function() {
    // It is a example of a public method because is revealed in the return statement
    var setCurrent = function() {
        //Here the variables current and length are used as private class properties  
        for (var i = ; i < this.length; i++) {                
                $(this.current).addClass('active');                 
        }
    }
    return { setCurrent: setCurrent };
}();

// Example of parameterless constructor  
NavigationNs.pagination = function() {}

NavigationNs.pagination.prototype = function() {
// It is a example of a private method because is not revealed in the return statement
    var reload = function(data) {
        // do something
    },
    // It the only public method, because it the only function referenced in the return statement
     getPage = function(link) {
        var a = $(link);

        var options = {url: a.attr('href'), type: 'get'}
        $.ajax(options).done(function(data) {            
           // after the the ajax call is done, it calls private method
           reload(data);
        });

        return false;
    }
    return {getPage : getPage}
}();
           

上面的代碼應該被放在一個單獨的js檔案中，像這樣使用：

var menuActive = new NavigationNs.active('ul.sidebar-menu li', );
menuActive.setCurrent();