Delight is a Ruby gem offering small yet useful extensions to the core Ruby classes. Those extensions are implemented as Refinements, which means they are only available in the scope where they are explicitly activated. This allows you to use them without worrying about polluting the global namespace or causing conflicts with other gems.

bundle add delight

In order to import all available methods use the global Delight::Enumerable refinement.

class MyClass
  using Delight::Enumerable

  def initialize(some_list)
    @some_list = some_list
  end

  def my_method
    some_list.select_by(country: "PL")
  end
end

The .detect! method is an extended version of the standard .detect. It will behave the same way as the standard .detect method, but it will also raise an error if no object is found. This is useful when you want to ensure that at least one object in the collection matches the given condition.

The .select_by method allows you to filter an array of objects based on a value(s) of single or multiple method values. Object in the collection must respond to the methods you are filtering by. Calling non-existing method will raise an NoMethodError.

# Following examples are equivalent:
addresses.select_by(country: "PL", city: "Warsaw")
addresses.select { it.country == "PL" && it.city == "Warsaw" }

Values are compared using === operator, so you can use any object that implements it. For example, you can use a range.

# Following examples are equivalent:
addresses.select_by(age: 18..)
addresses.select { it.age >= 18 }
addresses.select { 18.. === it.age }

Warning, be aware of of the === operator behavior. For example, if you would like to filter out the object by its class, you need to use the object itself as the argument, thus pass the itself method:

# Following examples are equivalent:
[18, 2.5, "foo"].select_by(itself: Numeric) # => [18, 2.5]
[18, 2.5, "foo"].select { it.is_a?(Numeric) } # => [18, 2.5]

The .detect_by method allows you to find the first object in a collection, which has a method (or methods) with value(s) matching the given argument(s). It works the same way as the .select_by method, but returns the first matching object instead of an array. The detect_by is to select_by as detect is to select.

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The gem is available as open source under the terms of the MIT License.