Posts tagged Event Domain

Ext JS: Custom Event Domains and Complex Controller Event Selectors

Dec 15th

A while back, I did a post on creating a custom Event Domain in Ext JS. If you’re new to the concept, Event Domains in Ext JS are simply classes that fire events which your controllers can listen to. The awesome part about domains, however, is that the “domain” of the events getting fired within your application are grouped together by type (read domain). This allows for very granular control over the event listeners that you construct in your controllers.

For example, the boilerplate for your controller since Ext JS 4.2.1 should now look something like this:

Ext.define('CustomController', {
    extend: 'Ext.app.Controller',
    init: function() {
        this.listen({
            controller: {},
            component: {},
            direct: {},
            global: {},
            store: {}
        })
    }
})

Ext JS comes with the 5 domains bolded above, and as we saw in the last post that you can create your own rather easily. In the example I shared, I created a custom event domain for “proxy”. With this custom domain setup, Ext JS will now monitor all events fired by the Ext.data.proxy.Proxy class, and our controllers can easily listen to those events and do whatever we need them to do. Pretty slick.

A Little Fancier

As nice as this works, I recently came across a scenario where I wanted a bit more More >

Event Domain, Router

ExtJS Quickie: Custom Event Domain

May 25th

Posted by existdissolve in Uncategorized

3 comments

With ExtJS 4.2 came the awesome concept of Event Domains. Basically, these allow you to let your Controllers know about ALOT more events within your applications. For example, in 4.1, you could use the control() method within your controller to listen to component-level events. However, with Event Domains, you can now listen to events in the following domains: Global, Controller, Component, Store.

This is awesome, but there are other domains that you might want to tap. No fear, the Event Domain is easily extensible to include others!

A Proxy Domain

In my applications, I generally have a single proxy that handles all my stores’ AJAX traffic. A common event listener for the proxy is the exception event, which fires in the case of a server error response. In the past, I’ve generally just added this to the listener config of the proxy itself, and went about my business.

The problem, of course, is that you generally want to DO something when an exception occurs, such as displaying an error message, resetting the state of a store, etc. The problem with defining the listener directly on the proxy is that you have to intrude your application upon the proxy to communicate the exception beyond the proxy.

But with a custom Event More >