Uniquely Identify KineticJS Shape

Question

I have a loop to see if a given shape collides with any other in a KineticJS program. Below is pseudocode for the situation

function hasCollision(shape, index) {
    var children = layer.children;
    for(var i = 0, l = children.length; i < l; i++) {
        if(i === index) continue; // Only check other shapes
        if(collision(shape, children[i]))
            return true;
    }
    return false;
}

What I don't like about this approach is that I have to save the index for each shape somewhere in my code. Additionally, the code will break if I remove elements from the array.

I read the documentation and couldn't find anything about comparing shapes etc., but I might have overlooked something. Does KineticJS already have a way to uniquely identify/compare instance of shapes? If not, is it OK to append custom data to a Node? Will it still work with serialization? Is doing this likely to break things with current or future versions of KineticJS?

EDIT: To be clear, this is the solution I'm considering

shape.uid = uid_factory++;

...

function hasCollision(shape) {
    var children = layer.children;
    for(var i = 0, l = children.length; i < l; i++) {
        var other = children[i];
        if(other.uid === shape.uid) continue; // Only check other shapes
        if(collision(shape, other))
            return true;
    }
    return false;
}

Answer 1

Yes.

You can assign a unique id to any Kinetic Node (shape, text, etc):

var shape123 = new Kinetic.Circle({
    id:(nextShapeId),
    ...

And you can get any node's id like this:

anyNode.getId();

And you can ask the stage to get you a reference to that node like this:

// use stage.find to fetch all nodes with an id == theId

var nodes = stage.find("#"+theId);

// nodes is a collection, so grab the first element

var myNode = nodes[0];