Progress bar for Leaflet map

There is the leaflet loading plugin https://github.com/ebrelsford/Leaflet.loading, it is straightforward to use. you could also look at the Spin plugin https://github.com/makinacorpus/Leaflet.Spin which is more customizable.

Thanks, but I already found this solution:

https://github.com/makinacorpus/Leaflet.Spin