Contents

module Enumerable

  # Like {https://ruby-doc.org/core/Enumerable.html#method-i-first
  # +Enumerable#first+}, but raises an exception if the Enumerable does
  # not contain the requested number of elements.
  #
  # @example
  #   [7, 8, 9].first     # == 7
  #   [7, 8, 9].first(1)  # == [7]
  #   [7, 8, 9].first(2)  # == [7, 8]
  #   [7, 8, 9].first(4)  # raises exception
  #   [].first            # raises exception
  #
  # @param n [Integer]
  #   requested number of elements
  # @return [Object, Array]
  # @raise [MiniSanity::Error]
  #   if the Enumerable does not contain the requested number of elements
  def first!(n = nil)
    result = n.nil? ? self.first : self.first(n)

    if (result.nil? && !self.any?{ true }) || (!n.nil? && result.length < n)
      raise MiniSanity::Error.new(nil,
        "Enumerable having at least #{n || 1} elements",
        self.inspect)
    end

    result
  end

end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
mini_sanity-1.1.0	lib/mini_sanity/util/enumerable.rb