I want to add a data source to a map in tmap (at the lower-right corner). The tm_credits() works for static map, however, I got a message "Credits not supported in view mode". tm_credits() doesn't work for interactive maps.
In the general leaflet.js environment the attribution control is shown by default in the lower right corner. It combines attribution attributes from individual layers and is not easily manipulated.
As far as I know there is no way to modify the attribution settings via the {tmap} package.
If creating maps via the {leaflet} package directly (i.e. not via {tmap}) you can add a custom text to the little grey attribution box commonly displayed in the lower right corner by setting text in the attribution argument of addTiles() call.