我對模塊設計模式的最佳實踐有疑問。下面的代碼是我們的一些組件編寫方式的一個例子(我們使用ExtJs,但這不應該太重要)。我們構建了很多像這樣的組件,並且我知道這完全不符合最佳實踐。有任何想法來清理代碼?ExtJS(JavaScript)模塊設計模式最佳實踐
Ext.ns("TEAM.COMPONENT");
function Foo() {
// Private vars
var privateNumber=0, myButton, privateInternalObject;
var numberField = new Ext.form.NumberField({
label : 'A NumberField!',
listeners : {
'change' : function(theTextField, newVal, oldVal) {
console.log("You changed: " + oldVal + " to: " + newVal);
}
}
});
// Some private methods
function changeNumField(someNumber) {
numberField.setValue(someNumber);
}
// Some public methods
this.publicFunctionSetNumToSomething() {
changeNumField(privateNumber);
}
/**
* Initializes Foo
*/
function init() {
// Do some init stuff with variables & components
myButton = new Ext.Button({
handler : function(button, eventObject) {
console.log("Setting " + numberField + " to zero!");
changeNumField(0);
},
text : 'Set NumberField to 0'
});
privateInternalObject = new SomeObject();
word = "hello world";
privateNumber = 5;
}
init();
return this;
};
我想了解一下這幾件事情,想問問,讓談話繼續下去:
- 如何重要的是它初始化變量,他們聲明時(在富頂部即)需要
- 如何,如果這個模塊的客戶端獲取到的狀態可能我重新初始化該對象的一部分,它的
foo
對象設置回它的原件 - 什麼樣的內存問題可能這樣的設計導致與我該如何重構來緩解那風險?
- 我在哪裏可以學到更多?是否有任何文章能夠解決這個問題,而不是過度依賴EcmaScript 5的最新和最大的功能?
2012-05-25 我只是想補充一點,我認爲這個問題(Extjs: extend class via constructor or initComponent?)是談話非常重要,特別是考慮到頂部投票的答案是從「前分機JS的共同創始人和核心開發」
更新2012-05-31 一個更此外,這個問題也應該鏈接(Private members when extending a class using ExtJS)。此外,這是我最喜歡的實施日期:
/*jshint smarttabs: true */
/*global MY, Ext, jQuery */
Ext.ns("MY.NAMESPACE");
MY.NAMESPACE.Widget = (function($) {
/**
* NetBeans (and other IDE's) may complain that the following line has
* no effect, this form is a useless string literal statement, so it
* will be ignored by browsers with implementations lower than EcmaScript 5.
* Newer browsers, will help developers to debug bad code.
*/
"use strict";
// Reference to the super "class" (defined later)
var $superclass = null;
// Reference to this "class", i.e. "MY.NAMESPACE.Widget"
var $this = null;
// Internal reference to THIS object, which might be useful to private methods
var $instance = null;
// Private member variables
var someCounter, someOtherObject = {
foo: "bar",
foo2: 11
};
///////////////////////
/* Private Functions */
///////////////////////
function somePrivateFunction(newNumber) {
someCounter = newNumber;
}
function getDefaultConfig() {
var defaultConfiguration = {
collapsible: true,
id: 'my-namespace-widget-id',
title: "My widget's title"
};
return defaultConfiguration;
}
//////////////////////
/* Public Functions */
//////////////////////
$this = Ext.extend(Ext.Panel, {
/**
* This is overriding a super class' function
*/
constructor: function(config) {
$instance = this;
config = $.extend(getDefaultConfig(), config || {});
// Call the super clas' constructor
$superclass.constructor.call(this, config);
},
somePublicFunctionExposingPrivateState: function(clientsNewNumber) {
clientsNewNumber = clientsNewNumber + 11;
somePrivateFunction(clientsNewNumber);
},
/**
* This is overriding a super class' function
*/
collapse: function() {
// Do something fancy
// ...
// Last but not least
$superclass.collapse.call(this);
}
});
$superclass = $this.superclass;
return $this;
})(jQuery);
[ExtJS的文檔指南](http://docs.sencha.com/ext-js/4-0/# !/指南)完全覆蓋了這方面的重要建議。至少看一下指南「類系統」,「組件」和「MVC應用程序體系結構」,它們將會幫助你很多。 – Tommi 2012-02-02 06:55:30