Question

I’d like to add some “ArrayCollection” like functionality to a ko.observableArray();

i.e
removeItemAt(index)//dispatches item removed event
addItem(item)//dispatches item added event
etc

I notice in most of the ko examples this is handled in the model. I have a fairly rich model with typed collections so would like to nest this in the collection/array itself.

Is this approach advisable with ko?

Answer 1

Extending observableArrays is easy and a perfectly reasonable thing to do.

The easiest way to accomplish this is to add functions to ko.observableArray.fn. There is now a documentation page for this technique.

This is a little bit different than what you are after, but here is a nice implementation of a dictionary in ko that may be of interest to you: https://github.com/jamesfoster/knockout.observableDictionary