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Contents
require 'singleton'
module GovukTechDocs
class UniqueIdentifierGenerator
include Singleton
Anchor = Struct.new(:id, :level)
attr_reader :anchors
def initialize
reset
end
def create(id, level)
anchor = heading_slug(id)
unless unique?(anchor)
anchor = prefixed_by_parent(anchor, level)
end
unless unique?(anchor)
anchor = suffixed_with_number(anchor)
end
@anchors << Anchor.new(anchor, level)
anchor
end
def reset
@anchors = []
end
private
def prefixed_by_parent(anchor, level)
closest_parent = @anchors.reverse.find { |a| a.level < level }
if closest_parent.nil?
anchor
else
[closest_parent.id, anchor].join("-")
end
end
def suffixed_with_number(text)
number = 2
anchor = "#{text}-#{number}"
until unique?(anchor)
anchor = "#{text}-#{number}"
number += 1
end
anchor
end
def unique?(value)
@anchors.none? { |a| a.id == value }
end
# https://github.com/vmg/redcarpet/blob/820dadb98b3720811cc20c5570a5d43c796c85fc/ext/redcarpet/html.c#L274-L305
def heading_slug(text)
text
.downcase
.strip
.gsub(%r{</?[^>]+?>}, '') # Remove HTML tags
.gsub(/[^0-9a-z]+/, '-') # Replace non-alphanumeric characters with dashes
.gsub(/\A-+|-+\z/, '') # Remove trailing dashes
end
end
end
Version data entries
32 entries across 32 versions & 2 rubygems