When working with ExtJS 4, you’ll often run into ambiguous error message like this one:

Uncaught TypeError: Cannot call method ‘substring’ of undefined

ext-all-debug.js line 4384

I recently ran into this while coding up an Ext application for another blog post, and I thought I’d share with you its root cause and solution.

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When I began using the SuperBoxSelect plugin at work, things went from good to awesome pretty damn quick. SuperBoxSelect offers a lot of great features that standard combo boxes don’t as well as directly integrating with the rest of ExtJS so you can do cool things like tie them to a JsonStore and write custom event handlers. Unfortunately, this plugin does support a commonly used feature among standard combo boxes: Shift+Click Selection. Read more

Recently, I was working on a side-project that involved allowing the user to press play and listen to a sample track from a list of tracks on their iPhone. While this functionality works great when the user is on WiFi, the delay between pressing ‘Play’ and hearing the song on a 3G connection makes the application feel sluggish and non-responsive. My first idea was to add an event listener to the ‘play’ event (or something similar) and show / hide some sort of loading message when the user selects ‘play’. Unfortunately, the Sencha Touch API doesn’t support any such event. However, there is a way around this. Read more