`... |> Enum.filter(...) |> List.first()` to `Enum.find(..., ...)`

[janpieper]

I just stumbled upon some code and I was wondering whether this could be something for styler to rewrite 🤔

movies
|> Enum.filter(&is_cool/1)
|> List.first()

to:

Enum.find(movies, &is_cool/1)

When using Enum.filter/2 followed by List.first/1 all items within the list are processed independently of whether the first would already be enough as it matched is_cool?/1. Replacing it with Enum.find/2 would stop the processing the items with the first match.

Even when List.first/3 is used, replacing it with Enum.find/3 would work.

movies
|> Enum.filter(&is_cool/1) # or Enum.reject/2
|> List.first(:not_found)

to:

Enum.find(movies, :not_found, &is_cool/1)

[novaugust]

Great suggestion, I'll make it happen :)

[novaugust]

thanks again jan, good little improvement. it'll be in styler's next release later this week

i didn't make the change for Enum.reject, as converting it would mean negating the function, which is nontrivial if the goal is to cover every shape of function (hard for fn x -> ... end, and inefficient for raw variables where you'd have to do something like &not reject_fun.(&1), adding another function call to the mess). in those cases, likely a custom (or upstreamed?) credo check would be best, to nudge the human to write something better