OpenLayers 4.6.4 Add / Remove layer event

Question

Is there an event that is triggered when a layer is added / removed from the map?

I saw something through the map.getLayers() group but it only seems to fired the "changed" event and doesn't contain what layer was added or removed.

Answer 1

Try propertychange event on layers. it's triggered when the layer's property changed.

map.getLayers().on("propertychange", function(e) {
    // triggered when layer added or removed
});

codepen: https://codepen.io/anon/pen/zRwWLg

or set change event on each layer

layer.on("change", function(e) {
    // then is sure what layer triggers the event
});