# `Bylaw.Credo.Check.Elixir.RejectCount`
[🔗](https://github.com/ryanzidago/bylaw/blob/v0.1.0-alpha.1/lib/bylaw/credo/check/elixir/reject_count.ex#L1)

## Basics

> #### This check is disabled by default. {: .neutral}
>
> [Learn how to enable it](`e:credo:config_file.html#checks`) via `.credo.exs`.

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

## Explanation

Use `Enum.count/2` instead of rejecting items and then counting the
remaining list.

## Examples

Avoid:

      users
      |> Enum.reject(&(&1.status == :inactive))
      |> Enum.count()

Prefer:

      Enum.count(users, &(&1.status != :inactive))

## Notes

`Enum.reject/2` builds an intermediate list just so `Enum.count/1` can
count it. The callback is also written in the negative, which makes the
kept values less obvious.

`Enum.count/2` performs the count in one pass without allocating the
rejected list, and the predicate describes the values being counted.

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`:

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

## Check-Specific Parameters

*There are no specific parameters for this check.*

## General Parameters

Like with all checks, [general params](`e:credo:check_params.html`) can be applied.

Parameters can be configured via the [`.credo.exs` config file](`e:credo:config_file.html`).

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*Consult [api-reference.md](api-reference.md) for complete listing*