There is no correct answer for this; it’s a highly personal preference. A lot of people prefer purity of grammar; these are the kind of folks who demand coding

There is no correct answer for this; it’s a highly personal preference. A lot of people prefer purity of grammar; these are the kind of folks who demand coding style guidelines and will be very unhappy if you violate their preference. They’re not wrong, but they have a very strong preference. A lot of people don’t care so much about particular style decisions, but they want readable code that is easy to understand, maintain and modify. I think a lot of the trailing-comma-preferring people fall into this category. But again, it’s a preference and isn’t right or wrong. There are probably also people who don’t care and compete in obfuscated code contests or try to minimize line counts by putting as many statements on each line as possible or otherwise writing genius-but-unreadable code by taking advantage of language and syntax idiosyncrasies. This is a preference too (although I consider it antisocial). My preference is, if it’s unambiguous, allow trailing commas wherever there are lists, because it makes cut and paste operations much easier. But at the end of the day that’s just my preference and not superior to anyone else.