[dragonwriter]

> My preference for when I have to do multiple operations on the same array (like filter then map) is "reduce". It's the most straightforward way other developers will understand what's going on.

There are definitely operations that are more intuitive as reduces, but any sequences consisting of exclusively filter, map, and/or flatMap are, IME and IMO, about the worst candidates.

(That said, because the JS filter, map, etc. operations are eager rather than lazy, sequenced operations produce intermediate arrays that may be undesirable especially with large datasets, so reduce can be desirable even without being more clear in intent.)