class HTML::Pipeline::TableOfContentsFilter

HTML filter that adds an 'id' attribute to all headers in a document, so they can be accessed from a table of contents.

Generates the Table of Contents, with links to each header.

Examples

TocPipeline =
  HTML::Pipeline.new [
    HTML::Pipeline::TableOfContentsFilter
  ]
# => #<HTML::Pipeline:0x007fc13c4528d8...>
orig = %Q(<h1>Ice cube</h1><p>is not for the pop chart</p>)
# => "<h1>Ice cube</h1><p>is not for the pop chart</p>"
result = {}
# => {}
TocPipeline.call(orig, {}, result)
# => {:toc=> ...}
result[:toc]
# => "<ul class=\"section-nav\">\n<li><a href=\"#ice-cube\">...</li><ul>"
result[:output].to_s
# => "<h1>\n<a id=\"ice-cube\" class=\"anchor\" href=\"#ice-cube\">..."

Constants

PUNCTUATION_REGEXP

Public Instance Methods

anchor_icon() click to toggle source

The icon that will be placed next to an anchored rendered markdown header

# File lib/html/pipeline/toc_filter.rb, line 29
def anchor_icon
  context[:anchor_icon] || "<span aria-hidden=\"true\" class=\"octicon octicon-link\"></span>"
end
call() click to toggle source
# File lib/html/pipeline/toc_filter.rb, line 33
def call
  result[:toc] = ""

  headers = Hash.new(0)
  doc.css('h1, h2, h3, h4, h5, h6').each do |node|
    text = node.text
    id = text.downcase
    id.gsub!(PUNCTUATION_REGEXP, '') # remove punctuation
    id.gsub!(' ', '-') # replace spaces with dash

    uniq = (headers[id] > 0) ? "-#{headers[id]}" : ''
    headers[id] += 1
    if header_content = node.children.first
      result[:toc] << %Q{<li><a href="##{id}#{uniq}">#{text}</a></li>\n}
      header_content.add_previous_sibling(%Q{<a id="#{id}#{uniq}" class="anchor" href="##{id}#{uniq}" aria-hidden="true">#{anchor_icon}</a>})
    end
  end
  result[:toc] = %Q{<ul class="section-nav">\n#{result[:toc]}</ul>} unless result[:toc].empty?
  doc
end