In short: from my experience, people like map and filter, but not reduce.

I use functions like map and filter all the time. When I put that code up for review, my peers rarely complain. I get plenty of feedback about other decisions, but not about my use of map and filter.

I cannot say the same for reduce. Often, when I’ve submitted a patch with reduce inside, I get a comment like, “this part is hard to read.” And I see reduce way less than map, filter, some, and so on.

Anecdotally, I have come to believe that programmers don’t like reduce as much.

I don’t know why, but I have a few theories:

• reduce is harder to read.
• reduce is less familiar.
• reduce can have worse performance compared to other options.
• reduce is less elegant in languages I use, like JavaScript, Python, and Swift. In my blissful stint as a Clojure developer, I did not get this feedback.
• I’m wrong, and I’m seeing a trend that’s not real.

I usually just change reduce to something else and move on. Even though I prefer it, I don’t usually care much. But it’s a little social phenomenon I’ve observed, and I thought I’d document it.

I’ve also noticed this less recently, possibly because code review is less thorough nowadays.

Do you notice this? Do you like reduce? Please tell me.