Can change programmatically Alloy callaback function dataTransform?

I'm using Alloy (the last version) and I defined a simple callback function in dataTransform. My questions are: 1) Can I change programmatically the callback function associated at attribute "dataTransform"? 2) Can I disable programmatically the callback function associated at attribute "dataTransform"?

E.g. In view.xml:

<TableView dataCollection="book" dataTransform="transformFunction"...>

In view.js:

function transformFunction(model) {
    var transform = model.toJSON();
    //TODO...
    return transform;
}

If it's not possible, can I render the transformFunction(model) a dummy function? (I mean: without the need of the trasformation of model into Json format.

My question is only related at performance tuning, I have a code which in same cases I have the need of a callback, in other case I have not the need of it.