Instead of partly rebuilding the zoom control, why not actually extending the original so it includes the full zoom control functionality?
by using L.Control.ZoomBar = L.Control.Zoom.extend
instead of L.Control.ZoomBar = L.Control.extend you can drop:
onRemove, _zoomIn, _zoomOut, _createButton and _updateDisabled
since these do nothing more than the already existing methods of the original Zoom Control.
On top of that you'll be making use of the original's ability to be used with screen readers and it's support for the zoomDelta option
Instead of partly rebuilding the zoom control, why not actually extending the original so it includes the full zoom control functionality?
by using
L.Control.ZoomBar = L.Control.Zoom.extendinstead of
L.Control.ZoomBar = L.Control.extendyou can drop:onRemove,_zoomIn,_zoomOut,_createButtonand_updateDisabledsince these do nothing more than the already existing methods of the original Zoom Control.
On top of that you'll be making use of the original's ability to be used with screen readers and it's support for the
zoomDeltaoption