Cannot read property '_icon' of undefined

I can’t reproduce this bug, but I get notifications from time to time on Opbeat, when ‘animationend’ is fired in L.MarkerClusterGroup.include.L.DomUtil.TRANSITION._animationEnd, and showMarker method tries to check if ((layer._icon || layer.__parent._icon) && !this._inZoomAnimation), and apparently __parent does not exist (see StackTrace at the bottom).

I’m not very familiar with Leaflet’s code, but if the __parent is not always available, would it be worth checking if ((layer._icon || (layer.__parent && layer.__parent._icon)) && !this._inZoomAnimation)?

StackTrace: L.MarkerClusterGroup.include.L.DomUtil.TRANSITION._animationEnd L.Mixin.Events.fireEvent showMarker ?

[ghybs]

Hi,

Well you are probably on it with Leaflet.Deflate.

If you actually remove your marker from MCG (besides from the map or not), then the marker loses its __parent property, and it will not get a new one because it is replaced by another object. The showMarker callback does not know it should now refer to that other object. Furthermore, even if that object is added to MCG, since it is a non-point feature, MCG will not be able to use (cluster) it and it will not assign a __parent property to it.

Why not using the callback of zoomToShowLayer to implement your conversion when triggering that method? That way you would ensure the marker is untouched until MCG no longer needs it. You would need to temporarily remove your listener from zoomend however.

We could still add a check on the existence of the __parent property, though. Better (but more complicated), we might need to assume that markers can be removed in the middle of an animation (as seems to be your case). I think the places that would be affected are zoomToShowLayer and the spiderfication animations.

Hope this helps.

[ghost]

Thanks for your ideas.

For now I will check myself for __parent before calling a method zoomToShowLayer. This should be the same as checking it inside the method, right? I will let you know if I’m still getting notifications after the change.