View Source Credo.Check.Refactor.MapInto (Credo v1.6.4)
This check has a base priority of high and requires Elixir < 1.8.0.
Explanation
Enum.into/3 is more efficient than Enum.map/2 |> Enum.into/2.
This should be refactored:
[:apple, :banana, :carrot]
|> Enum.map(&({&1, to_string(&1)}))
|> Enum.into(%{})to look like this:
Enum.into([:apple, :banana, :carrot], %{}, &({&1, to_string(&1)}))The reason for this is performance, because the separate calls to
Enum.map/2 and Enum.into/2 require two iterations whereas
Enum.into/3 only requires one.
NOTE: This check is only available in Elixir < 1.8 since performance improvements have since made this check obsolete.
Check-Specific Parameters
There are no specific parameters for this check.
General Parameters
Like with all checks, general params can be applied.
Parameters can be configured via the .credo.exs config file.