Bylaw.Credo.Check.Elixir.PreferEnumUniqBy (bylaw_credo v0.4.0)

Basics

This check has a base priority of high and works with any version of Elixir.

Explanation

Prefer Enum.uniq_by/2 before projecting fields with Enum.map/2.

Deduplicating the original records keeps the identity rule attached to the source data and avoids projecting values that will only be discarded as duplicates. It also makes the intended uniqueness key visible in one place.

Examples

Avoid:

  items
  |> Enum.map(& &1.step)
  |> Enum.uniq()

Prefer:

  items
  |> Enum.uniq_by(& &1.step)
  |> Enum.map(& &1.step)

This keeps the uniqueness rule attached to the original items instead of first projecting values and then deduplicating the projected list.

Notes

This check uses static AST analysis, so it favors clear source-level patterns over runtime behavior.

Options

This check has no check-specific options. Configure it with an empty option list.

Usage

Add this check to Credo's checks: list in .credo.exs:

%{
  configs: [
    %{
      name: "default",
      checks: [
        {Bylaw.Credo.Check.Elixir.PreferEnumUniqBy, []}
      ]
    }
  ]
}

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.