borisyankov/DefinitelyTyped — pull request #1025 by flxf (2013-09-08 21:25:01+00:00)
Title: Fix leaflet.d.ts, TileLayerOptions.subdomains is flexibly typed

From the comments, subdomains can be a string or an array of strings. We
can't make any strong type inference from the interface.

Quote:
"Subdomains of the tile service. Can be passed in the form of one string (where
each letter is a subdomain name) or an array of strings."