Ext JS Stores and Complex Objects

I recall reading developers should think of records in a store as a row in a database where开发者_开发知识库 each column is a simple data type. We store complex JS objects in Ext JS stores without any apparent ramifications.

Does anybody know of pitfalls with storing JS objects in an Ext JS store?

Modern web browsers have gotten very good at managing this kind of memory usage and processing speed. Internally we had implemented the sort of record associations that extjs 4 has built-in now, and have scenarios with ~250k complex nested records stored without any real problem. I believe that the negligible impact on performance would continue to hold up for a long time, as it also is pretty good about cleaning up its own memory usage after itself. We mirrored our web server's ORM models to extjs record definitions, and regularly query against these nested stores in much of the same ways that we would hit a more traditional database. You have to be careful what you do with it, e.g., trying to render a grid of 250k records at once will not work out very well. But that is almost entirely the impact of dom rendering and not the iteration or storage of the record/store data. All of this seems to be even more true when testing with the recent extjs 4 beta releases.

Looking at the Ext JS source it seems like a Store is a wrapper around an Object which offers sorting / filter and event functionality. It's a simple key/value pair.

The complexity of the object should not cause any problems.

Now treating a Store as anything but a wrapper around an key/value pair collection is going to cause problems. Thinking it's like a table is going to cause problems. That kind of misunderstanding leads to poorly designed code.

A Store should be treated as a Bag of key/value data with helper methods to organise that bag.

I suppose there can potentially be a performance impact if your JS objects are very large, it could take some time if you end up doing a lot of serialization/deserializtion of those JS objects. If you are dealing with grids, you can mitigate these by use of pagination.

Stores are not necessarily used strictly for grid rows. They are used in many Ext objects such as comboboxes (drop down menus). Here it is used with a key/value pair. Usually this is done for a value and a displayValue relationship for the data.

If you need an even lower level object to work with, check out the Ext.util.MixedCollection object. There are lots of fun stuff in there. It's basically a hashmap of key/value pairs. I believe in the Ext source code, Stores use these objects at its core.