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.

Read more

Recently, while working with a model and proxy in ExtJS 4, I ran into the issue where the model’s proxy would call the ‘create’ action instead of ‘update’ when saving changes to an existing record. Read more