Appcelerator和CommonJS模块(缓存和循环引用)

Question

这是事情:

我正在使用CommonJS方式使我的移动(iPhone/Android)应用程序模块化.这并不奇怪.但有一点我无法理解.

CommonJS让我创建了STATIC私有变量,这让我可以轻松创建单例.至少,我认为这是因为获取require()d 的文件的内容只读取一次,然后每次都返回export对象(只初始化一次).

但是当我创建如下所示的循环引用时,每次都会执行包含模块内的代码.

等等...... 有趣的是,在我写这个问题的时候,我突然意识到require()在下一个问题开始之前没有任何调用完成(因此下面显示了堆栈溢出).

关于我是否正常的任何想法？这是凌晨5点过来的所以,所以我所关注的所有赌注都是关闭的:D.

例子:

看到这段代码,它定义了一个单例:

/* Singleton.js */

exports.getSingleton = getSingleton;

function getSingleton(name) {
  if (!instance) {
    instance = new Thing(name);
  }

  return instance;
}

function Thing(name) {
  this.name = name;
}

var instance;

我require()这个文件是这样的:

var theFirstThing = require('Singleton').getSingleton('first');
Ti.API.info('first: ' + theFirstThing.name)

var possiblyAnotherOtherThing = require('Singleton').getSingleton('second');
Ti.API.info('second: ' + possiblyAnotherOtherThing.name);

输出是:

[DEBUG] loading: /path/to/sim/MyApp.app/app.js, resource: app_js
[DEBUG] loading: /path/to/sim/MyApp.app/Singleton.js, resource: Singleton_js
[INFO] first: first
[INFO] second: first

为什么那样的循环引用如下所示不起作用？(如果你愿意的话,我可能已经自己研究了这个,评论/回答).

app.js

require('Banana');

Pinapple.js

require('Banana');

Banana.js

require('Pineapple');

因为输出是这样的:

[DEBUG] loading: /path/to/simulator/MyApp.app/app.js, resource: app_js
[DEBUG] loading: /path/to/simulator/MyApp.app/Banana.js, resource: Banana_js
[DEBUG] loading: /path/to/simulator/MyApp.app/Pineapple.js, resource: Pineapple_js
[DEBUG] loading: /path/to/simulator/MyApp.app/Banana.js, resource: Banana_js
[DEBUG] loading: /path/to/simulator/MyApp.app/Pineapple.js, resource: Pineapple_js
[DEBUG] loading: /path/to/simulator/MyApp.app/Banana.js, resource: Banana_js
[DEBUG] loading: /path/to/simulator/MyApp.app/Pineapple.js, resource: Pineapple_js
[DEBUG] loading: /path/to/simulator/MyApp.app/Banana.js, resource: Banana_js

/* etcetera (total of 15 times back and forth) */

[DEBUG] loading: /path/to/simulator/MyApp.app/Pineapple.js, resource: Pineapple_js
[DEBUG] loading: /path/to/simulator/MyApp.app/Banana.js, resource: Banana_js
[DEBUG] loading: /path/to/simulator/MyApp.app/Pineapple.js, resource: Pineapple_js
[ERROR] Script Error = Maximum call stack size exceeded. (unknown file)

Answer 1

我也在使用Appcelerator Titanium中的CommonJS模块来构建移动应用程序.我为解决循环依赖问题所做的是:如果A和B是2个循环相关的模块,则在实际需要使用它之前需要 B中的(A),反之亦然.在我的情况下,我只在单击某个按钮时才需要A内部B,所以我在按钮的click事件监听器中放入了一个require(A).希望有所帮助.