3 ms·

Downside: Still going over the array multiple times.

• agumonkey 7y ago
  fair point, in js it will, in other languages that idiom gets deforested into a single pass though
  • chris_st 7y ago
    Cool, which languages do this?
    • cofunctor 7y ago
      This ought to work with any lazy language (or lazy data structure), which is one of the huge benefits of laziness for FP.
• sli 7y ago
  You could (usually, but not always) compose the functions you're passing into filter and map and use reduce instead to do both operations in a single pass. (Edit: This is a big point in the article -- apologies, I hadn't finished reading it yet.)