Add a core `rouge` filter to correctly highlight pages using Jekyll

lib/docs/filters/core/rouge.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module Docs
+  class RougeFilter < Filter
+    def call
+      css('div.highlighter-rouge').each do |node|
+        node['data-language'] = node['class'][/language-(\w+)/, 1] if node['class']
+        node.content = node.content.strip
+        node.name = 'pre'
+      end
+
+      css('.highlighter-rouge').remove_attr('class')
+
+      doc
+    end
+  end
+end

lib/docs/filters/electron/clean_html.rb

@@ -22,14 +22,6 @@ module Docs
           node.name = node.name.sub(/\d/) { |i| i.to_i - 1 } unless node.name == 'h3' && node.at_css('code')
         end if !at_css('h2') && at_css('h4')
 
-        css('div.highlighter-rouge').each do |node|
-          node['data-language'] = node['class'][/language-(\w+)/, 1] if node['class']
-          node.content = node.content.strip
-          node.name = 'pre'
-        end
-
-        css('.highlighter-rouge').remove_attr('class')
-
         css('pre').each do |node|
           node.content = node.content
         end

lib/docs/filters/flow/clean_html.rb

@@ -52,13 +52,6 @@ module Docs
           node.replace(pre)
         end
 
-        css('div.highlighter-rouge').each do |node|
-          node['data-language'] = node['class'][/language-(\w+)/, 1] if node['class']
-          node.content = node.content.strip
-          node.name = 'pre'
-        end
-
-        css('.highlighter-rouge').remove_attr('class')
       end
     end
   end

lib/docs/filters/yarn/clean_html.rb

@@ -42,14 +42,6 @@ module Docs
             node.name = node.name.sub(/\d/) { |i| i.to_i - 1 }
           end
         end
-
-        css('div.highlighter-rouge').each do |node|
-          node['data-language'] = node['class'][/language-(\w+)/, 1] if node['class']
-          node.content = node.content.strip
-          node.name = 'pre'
-        end
-
-        css('.highlighter-rouge').remove_attr('class')
       end
     end
   end

lib/docs/scrapers/electron.rb

@@ -8,7 +8,7 @@ module Docs
       code: 'https://github.com/electron/electron'
     }
 
-    html_filters.push 'electron/clean_html', 'electron/entries'
+    html_filters.push 'electron/clean_html', 'electron/entries', 'rouge'
 
     options[:trailing_slash] = true
     options[:container] = '.page-section > .container, .page-section > .container-narrow'

lib/docs/scrapers/flow.rb

@@ -8,7 +8,7 @@ module Docs
       code: 'https://github.com/facebook/flow'
     }
 
-    html_filters.push 'flow/entries', 'flow/clean_html', 'title', 'parse_cf_email'
+    html_filters.push 'flow/entries', 'flow/clean_html', 'title', 'parse_cf_email', 'rouge'
 
     options[:trailing_slash] = false
     options[:root_title] = 'Flow'

lib/docs/scrapers/yarn.rb

@@ -8,7 +8,7 @@ module Docs
       code: 'https://github.com/yarnpkg/yarn'
     }
 
-    html_filters.push 'yarn/entries', 'yarn/clean_html', 'title', 'parse_cf_email'
+    html_filters.push 'yarn/entries', 'yarn/clean_html', 'title', 'parse_cf_email', 'rouge'
 
     options[:root_title] = 'Yarn'
     options[:trailing_slash] = false