Javascript OpenLayers before zoom event listener

Question

I am trying to set up OpenLayers to not display the vector layer just before a zoom starts and make it reappear after a zoom ends. I have the zoom ends part already established

Answer 1

Here is a easy to add the 'BeforeZoom' event to the OpenLayers . Just add the code below to where you created your map object.

map.zoomToProxy = map.zoomTo;
map.zoomTo =  function (zoom,xy){
    //Your Before Zoom Actions

    //If you want zoom to go through call
    map.zoomToProxy(zoom,xy); 
    //else do nothing and map wont zoom
};

How this works:

For any kind of zooming activity, OpenLayers API ultimately calls the function called zoomTo. So before overriding it, we copy that function to a new function called 'zoomToProxy'. The we override it and add our conditional zoom logic. If we want the zoom to happen we just call new proxy function :)