View Source Credo.Check.Refactor.FilterCount (Credo v1.7.0)
This check has a base priority of high and works with any version of Elixir.
explanation
Explanation
Enum.count/2 is more efficient than Enum.filter/2 |> Enum.count/1.
This should be refactored:
[1, 2, 3, 4, 5]
|> Enum.filter(fn x -> rem(x, 3) == 0 end)
|> Enum.count()to look like this:
Enum.count([1, 2, 3, 4, 5], fn x -> rem(x, 3) == 0 end)The reason for this is performance, because the two separate calls
to Enum.filter/2 and Enum.count/1 require two iterations whereas
Enum.count/2 performs the same work in one pass.
check-specific-parameters
Check-Specific Parameters
There are no specific parameters for this check.
general-parameters
General Parameters
Like with all checks, general params can be applied.
Parameters can be configured via the .credo.exs config file.