Contents

# Utility Function

## Introduction

A _Utility Function_ is any instance method that has no dependency on the state of the instance.

_Utility Function_ is heavily related to _[Feature Envy](Feature-Envy.md)_, please check out the explanation there why _Utility Function_ is something you should care about.

## Example

Given

```Ruby
class UtilityFunction
  def showcase(argument)
    argument.to_s + argument.to_i
  end
end
```

`reek` would report:

```
test.rb -- 2 warnings:
  [2]:UtilityFunction#showcase doesn't depend on instance state (UtilityFunction)
```

## Current Support in reek

_Utility Function_ will warn about any method that:

* is non-empty
* does not override an inherited method
* calls at least one method on another object
* doesn't use any of self's instance variables
* doesn't use any of self's methods

## Differences to _Feature Envy_

_[Feature Envy](Feature-Envy.md)_ is only triggered if there are some references to self and _Utility Function_ is triggered if there are no references to self.

## Configuration

`reek`'s _Utility Function_ detector supports the [Basic Smell Options](Basic-Smell-Options.md).

Version data entries

10 entries across 10 versions & 1 rubygems

Version	Path
reek-3.3.1	docs/Utility-Function.md
reek-3.3.0	docs/Utility-Function.md
reek-3.2.1	docs/Utility-Function.md
reek-3.2	docs/Utility-Function.md
reek-3.1	docs/Utility-Function.md
reek-3.0.4	docs/Utility-Function.md
reek-3.0.3	docs/Utility-Function.md
reek-3.0.2	docs/Utility-Function.md
reek-3.0.1	docs/Utility-Function.md
reek-3.0.0	docs/Utility-Function.md