Check whether tiles are already cached.

[arenol]

I have an application that is supposed to work on cell phones out it the forest without mobile coverage. Hence, it is possible to cache the maps before going out, and I've used PouchDBCahed for this purpose.

The application can be found here, and the tiles can be cached by pressing the blue button below the map.

First time, it takes a few minutes to cache all tiles upon startup.

When you open the page a later time and then press the blue button, it takes only a few seconds to cache all the tiles.

This suggests that the tiles are still in the cache.

Is there a way I can check for this when initializing the map, so I can use the cache and gray out the blue button right at the start?