Added rake task to add header anchors to h1-h6 after build

rakelib/build.rake

@@ -1,5 +1,6 @@
 require 'rake/clean'
 require 'yaml'
+require 'nokogiri'
 
 CLEAN.include('build')
 CLEAN.include('resources')
@@ -37,7 +38,53 @@ task :check_for_title do
   end
 end
 
+desc 'Add anchor tag to all the headers'
+task :header_anchors do
+  begin
+    Dir["public/**/*.html"].select {|file|
+      html = Nokogiri::HTML(open(file))
+      puts "Parsing file: " + file.pathmap
+      html.css('h1,h2,h3,h4,h5,h6').each {|header|
+        if header['id'] == nil || header['id'].exclude?('searchResultTitle')
+          id               = header['id'] || generate_id(header.text)
+          i                = Nokogiri::XML::Node.new "i", html
+          i['class']       = "fa fa-link"
+          i['aria-hidden'] = "true"
+
+          a          = Nokogiri::XML::Node.new "a", html
+          a['href']  = '#' + id
+          a['class'] = "header-anchor"
+          a.content  = "a"
+
+          i.parent = a
+          header.children.first.add_previous_sibling(a)
+        end
+      }
+      File.write(file, html.to_html)
+    }
+    puts 'Successfully created header anchors!!!'
+  rescue Exception => e
+    puts 'Failed: Error while generating header anchors!!!' + e.message
+    puts e.backtrace
+  end
+end
+
 desc "build the documentation"
-task :compile => [:clean, :init, :check_for_title, :run_hugo]
+task :compile => [:clean, :init, :check_for_title, :run_hugo, :header_anchors]
 task :build => [:compile, "static_checks:all"]
 
+private_methods
+
+def generate_id text
+  downcase       = text.strip.downcase
+  id_with_spaces = downcase.gsub! /[^a-zA-z0-9_]+/, ' '
+  if id_with_spaces === nil
+    return downcase
+  end
+  id_with_spaces = id_with_spaces.strip
+  id             = id_with_spaces.gsub! /[ ]+/, '-'
+  if id === nil
+    return id_with_spaces
+  end
+  id
+end

themes/hugo-book/assets/book.scss

@@ -369,3 +369,36 @@ a.navigation {
   font-weight: 600;
   font-size: 22px;
 }
+
+a.header-anchor {
+  display: none;
+  margin-left: -15px;
+  cursor: pointer;
+  position: absolute;
+  top: 20px;
+  left: 0;
+  bottom: 0;
+}
+
+h2, h3 {
+  a.header-anchor {
+    margin-left: -10px;
+  }
+}
+
+h4, h5, h6 {
+  a.header-anchor {
+    margin-left: -8px;
+    top: 0;
+  }
+}
+
+h1, h2, h3, h4, h5, h6 {
+  position: relative;
+}
+
+h1:hover, h2:hover, h3:hover, h4:hover, h5:hover, h6:hover {
+  a.header-anchor {
+    display: inline-block;
+  }
+}

yarn.lock

@@ -1032,7 +1032,7 @@ lru-cache@^4.0.1:
     pseudomap "^1.0.2"
     yallist "^2.1.2"
 
-lunr@^2.3.5:
+[email protected].6:
   version "2.3.6"
   resolved "https://registry.yarnpkg.com/lunr/-/lunr-2.3.6.tgz#f278beee7ffd56ad86e6e478ce02ab2b98c78dd5"
   integrity sha512-swStvEyDqQ85MGpABCMBclZcLI/pBIlu8FFDtmX197+oEgKloJ67QnB+Tidh0340HmLMs39c4GrkPY3cmkXp6Q==