How to check if a leaflet layer is already added on the map?

Question

I built a simple map app where I have a layer on top of a map. In Leaflet, how can I check if the layer is already present?

Answer 1

There is a hasLayer method provided by Leaflet. It's a Boolean that returns true if already on the map.

For example, map.hasLayer(yourUserDefinedLayerNameGoesHere); will return true if it is added to the map or false if not.

For more details search the Leaflet documentation for hasLayer at: http://leafletjs.com/reference-1.2.0.html#map-methods-for-layers-and-controls