Comment by latexr
2 hours ago
I used to use em dashes with spaces. I started using them without when I was more into reading style guides and it was—if I recall correctly—the Chicago Manual of Style which doesn’t use spaces. This was way before LLMs came onto the scene as a consumer technology.
The Chicago Manual indeed advises against spaces, but it’s written for books. AP Stylebook — that recommends spaces — is for papers. Comments are an even shorter form, so they’re closer to AP than to Chicago.
When I go to print, I use hairspace, but it’s not worth the trouble in comments.