Services that render fenced code blocks tend to remove whitespace. They'll display these two code blocks the same way, trimming the blank lines from the second example.
GitHub does this, as does Deckset. Deckset also adjusts your code's font size based on how many lines are in the block, which means these two code blocks would have different font sizes on their slides. Sometimes I don't want that to happen, like when building a series of slides that fill in different pieces of an example and should look consistent.
I cheat this feature putting a non-breaking space on the last line. On Mac, I can do this with
OPTION + SPACE. I can see the character in Vim ('
+'), but it's invisible on the slide, and it prevents Deckset from collapsing the line it's on, forcing the code block to the length I choose.