是否有可能通过ember.js定期通知观察者计算的属性？ [英] Is it possible to periodically notify observers of a computed property with ember.js?
问题描述
我正在尝试实现以下简单的用例：有一个ember模板定期显示当前时间。我找到了一种办法，但我怀疑有更好/更简单的方法。这是我做的：
I am trying to implement the following simple use case: have an ember template periodically display the current time. I have found a way to do it, but I suspect that there is a better/simpler way. Here is what I do:
-
在我的控制器中，我有一个dirtyFlag属性。我使用这个方法来触发观察者的通知（因此我的模板）。
In my controller, I have a dirtyFlag property. I use this as a trick to trigger the notification of observers (hence of my template).
当应用程序准备就绪时，我会定时启动一个定时器更改 dirtyFlag属性的值。
When the application is ready, I start a timer to periodically change the value of the dirtyFlag property.
我想避免使用dirtyFlag属性，基本上我想知道是否有一种方式来表达类似于的所有观察者在currentTime计算属性应更新并获取此属性的新值。
I would like to avoid using the dirtyFlag property, and essentially I am wondering if there is a way to express something like all observers on the currentTime computed property should update and get the new value for this property.
var App = Ember.Application.create({
ready: function() {
setInterval(function() {
console.info("Updating clock (" + new Date() + ")");
App.theClockController.set('dirtyFlag', new Date());
}, 1000)
}
});
App.ClockController = Ember.ObjectController.extend({
dirtyFlag: null,
currentTime: function() {
return new Date();
}.property('dirtyFlag')
});
推荐答案
我建议使用标准属性来存储缓存时间值，然后根据需要绑定到它。例如：
I would recommend using a standard property to store the cached time value and then binding to it as needed. For example:
App = Ember.Application.create({
ready: function() {
setInterval( function() {
console.info("Updating clock (" + new Date() + ")");
App.set('currentTime', new Date());
}, 1000)
}
});
App.ClockController = Ember.Controller.extend({
currentTimeBinding: Ember.Binding.oneWay('App.currentTime')
});
请看这个jsfiddle一个工作示例： http://jsfiddle.net/nzLyh/1/
See this jsfiddle for a working example: http://jsfiddle.net/nzLyh/1/
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