OpenLayers: Zoom multiple layers to best common extent?

Question

Is there an easy way (other than getting layer extents separately and doing the calculation) to group the layers and zoom to the extent that is best for displaying shapes on all of the grouped layers?

Answer 1

Solution:

bounds = @get('siblingsLayer').getDataExtent()
bounds.extend(@get('vectorLayer').getDataExtent())
bounds.extend(@get('parentLayer').getDataExtent())

@get('map').zoomToExtent(bounds)

Answer 2

This one worked for me.

Code:

var allLayers = map.getLayers();
var length = allLayers.getLength();
var layerArray = ['Layer1', 'Layer2', ..., 'LayerN'];
var extent = ol.extent.createEmpty();
for (var i = 0; i < length; i++) {
    var existingLayer = allLayers.item(i);
    for (var j = 0; j < layerArray.length; j++) {
        if (existingLayer.get('title') == layerArray[j]) {
            ol.extent.extend(extent,existingLayer.getSource().getExtent());
        }
    }
}
map.getView().fit(extent, map.getSize());

Example:

I have added two layers and pointed to one layer among them.

After calling the API, my view updated and focused to both the layers: