Hash#breadcrumbs

hash_breadcrumbs.rb

class Hash
	
  def self.breadcrumbs(hash)
    hash.flat_map do |k,v|
      if v.is_a?(Hash)
        breadcrumbs(v).map{|p| [k, *p]}
      else
        [k]
      end
    end
  end

  def breadcrumbs(**options)
    @_all_trails ||= begin
      base = self.class.breadcrumbs(self)
      fragments = base.flat_map{|p| p.map.with_index(1){|_,i| p.slice(0,i) } }

      (base + fragments).uniq
    end

    trails = @_all_trails

    if options.has_key?(:ending_in)
      tail = options[:ending_in]
      tail = [tail] unless tail.is_a? Array

      trails = trails.select{|p| p.slice((- tail.length)..-1) == tail }
    end

    if options[:with_values] == true
      trails.map{|p| [p, dig(*p)] }.to_h
    else
      trails
    end
  end

end