Class: Qiita::Markdown::Filters::HtmlToc

Inherits:
HTML::Pipeline::Filter
  • Object
show all
Defined in:
lib/qiita/markdown/filters/html_toc.rb

Instance Method Summary collapse

Instance Method Details

#call ⇒ Nokogiri::HTML::DocumentFragment

Returns:

  • (Nokogiri::HTML::DocumentFragment) 


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# File 'lib/qiita/markdown/filters/html_toc.rb', line 8

def call
  headings = doc.search("h1, h2, h3, h4, h5, h6")
  return "" if headings.empty?

  toc = %W[<ul>\n]
  top_level = nil
  last_level = nil
  depth = 1

  headings.each do |node|
    heading_rank = node.name.match(/h(\d)/)[1].to_i

    # The first heading is displayed as the top level.
    # The following headings, of higher rank than the first, are placed as top level.
    top_level ||= heading_rank
    current_level = [heading_rank, top_level].max

    link = toc_with_link(node.text, node.attributes["id"]&.value)
    toc << (nest_string(last_level, current_level) + link)

    depth += current_level - last_level if last_level

    last_level = current_level
  end

  toc << ("</li>\n</ul>\n" * depth)
  toc.join
end