Monitor changes to an array object

Question

I have no idea if this is possible at all, but it would save me from a lot of stress and bad code. Is it possible to monitor whenever an array gets updated? For example, method A changes the array a=[1,2,3] to a=[1,2,3,4], is it possible to have a sort of delegate that gets triggered when a is updated?

Clinton

Why not implement your own protocol observable and make the arrays in question conform to that? – Cenis

Alternatively make a wrapper object that, when updating the Array, calls a didChangeArray() or flips a public bool that you can check. – Rundown

It's time for bed here. I'll provide it tomorrow (unless someone else comes up wit a smart idea) – Cenis

Answer 1

If your array is a property in your class, you can use property observers. willSet is called before the change, didSet is called after. It is really easy.

var myArray:[Int] = [1, 3, 4] {
    didSet {
        println("arrayChanged")
    }
}

This will print array changed if I add an Int, remove and Int, etc. I generally put it on one line though:

var myArray:[Int] = [1, 3, 4] { didSet { println("arrayChanged") } }

Bipartisan

Thank you, it was very helpful – Lidstone

Is there any way to monitor internal array changes? Like myArray.append(x)? – Estis

@PavelAlexeev If you define the set for your array it will call for all removeAll, append etc changes. – Robbyrobbyn