It's actually only your post that made me realize people don't normally put spaces around em dash. In French, Russian and a bunch of other languages proper typesetting is to use em dash as a standard dash character, and you always put spaces around them. So I did it in English as well, for many years now.
(I also now looked up and found out that in Spanish, apparently, you are supposed to put space only on one side of the dash, when used as a direct speech separator.)
(I also now looked up and found out that in Spanish, apparently, you are supposed to put space only on one side of the dash, when used as a direct speech separator.)