Trailing in languages which support ending the last item with a comma as this follows the usage of the semicolon. [ 1, 2, ] Leading otherwise as no

Trailing in languages which support ending the last item with a comma as this follows the usage of the semicolon. [ 1, 2, ] Leading otherwise as no language I can remember supports a leading comma on the first item: [ 1 , 2 ] The entire point of this is to avoid needing to edit the prior line when inserting items into an existing lexical list this makes the diffs just: + instead of: - + + If you don't care about how your line diffs look, don't bother. Just auto-format your code instead.