Add RxJS

The current RxJS documentation site is https://rxjs.dev/.

It is very similar to Angular documentation site (https://angular.io/) so I reused most code.

Images on the documentation site seem to be broken and so the scrapper cannot download them. You can see an example of a broken image at https://rxjs.dev/api/operators/buffer.

Related to https://github.com/freeCodeCamp/devdocs/issues/939

assets/stylesheets/application.css.scss

@@ -94,6 +94,7 @@
         'pages/rfc',
         'pages/rubydoc',
         'pages/rust',
+        'pages/rxjs',
         'pages/sinon',
         'pages/socketio',
         'pages/sphinx',

assets/stylesheets/pages/_rxjs.scss

@@ -0,0 +1,24 @@
+._rxjs {
+  @extend %simple;
+
+  .pre-title { @extend %pre-heading; }
+
+  .breadcrumbs { @extend %note; }
+  .banner { @extend %note-green; }
+  code.stable { @extend %label-green; }
+  code.experimental { @extend %label-orange; }
+  code.deprecated { @extend %label-red; }
+  .alert.is-important { @extend %note-red; }
+  .alert.is-helpful, .breadcrumbs { @extend %note-blue; }
+
+  .breadcrumbs { padding-left: 2em; }
+
+  img { margin: 1em 0; }
+
+  .location-badge {
+    font-style: italic;
+    text-align: right;
+  }
+
+  td h3 { margin: 0 !important; }
+}

lib/docs/filters/rxjs/clean_html.rb

@@ -0,0 +1,101 @@
+module Docs
+  class Rxjs
+    class CleanHtmlFilter < Filter
+      def call
+        if root_page?
+          css('.card-container').remove
+          at_css('h1').content = 'RxJS Documentation'
+        end
+
+        css('br', 'hr', '.material-icons', '.header-link', '.breadcrumb').remove
+
+        css('.content', 'article', '.api-header', 'section', '.instance-member').each do |node|
+          node.before(node.children).remove
+        end
+
+        css('label', 'h2 > em', 'h3 > em').each do |node|
+          node.name = 'code'
+        end
+
+        css('h1 + code').each do |node|
+          node.before('<p></p>')
+          while node.next_element.name == 'code'
+            node.previous_element << ' '
+            node.previous_element << node.next_element
+          end
+          node.previous_element.prepend_child(node)
+        end
+
+        css('td h3', '.l-sub-section > h3', '.alert h3', '.row-margin > h3', '.api-heading ~ h3', '.api-heading + h2', '.metadata-member h3').each do |node|
+          node.name = 'h4'
+        end
+
+        css('.l-sub-section', '.alert', '.banner').each do |node|
+          node.name = 'blockquote'
+        end
+
+        css('.file').each do |node|
+          node.content = node.content.strip
+        end
+
+        css('.filetree .children').each do |node|
+          node.css('.file').each do |n|
+            n.content = "  #{n.content}"
+          end
+        end
+
+        css('.filetree').each do |node|
+          node.content = node.css('.file').map(&:inner_html).join("\n")
+          node.name = 'pre'
+          node.remove_attribute('class')
+        end
+
+        css('pre').each do |node|
+          node.content = node.content.strip
+
+          node['data-language'] = 'typescript' if node['path'].try(:ends_with?, '.ts')
+          node['data-language'] = 'html' if node['path'].try(:ends_with?, '.html')
+          node['data-language'] = 'css' if node['path'].try(:ends_with?, '.css')
+          node['data-language'] = 'js' if node['path'].try(:ends_with?, '.js')
+          node['data-language'] = 'json' if node['path'].try(:ends_with?, '.json')
+          node['data-language'] = node['language'].sub(/\Ats/, 'typescript').strip if node['language']
+          node['data-language'] ||= 'typescript' if node.content.start_with?('@')
+
+          node.before(%(<div class="pre-title">#{node['title']}</div>)) if node['title']
+
+          if node['class'] && node['class'].include?('api-heading')
+            node.name = 'h3'
+            node.inner_html = "<code>#{node.inner_html}</code>"
+          end
+
+          node.remove_attribute('path')
+          node.remove_attribute('region')
+          node.remove_attribute('linenums')
+          node.remove_attribute('title')
+          node.remove_attribute('language')
+          node.remove_attribute('hidecopy')
+          node.remove_attribute('class')
+        end
+
+        css('h1[class]').remove_attr('class')
+        css('table[class]').remove_attr('class')
+        css('table[width]').remove_attr('width')
+        css('tr[style]').remove_attr('style')
+
+        if at_css('.api-type-label.module')
+          at_css('h1').content = subpath.remove('api/')
+        end
+
+        css('th h3').each do |node|
+          node.name = 'span'
+        end
+
+        css('code code').each do |node|
+          node.before(node.children).remove
+        end
+
+        doc
+      end
+    end
+  end
+end

lib/docs/filters/rxjs/entries.rb

@@ -0,0 +1,23 @@
+module Docs
+  class Rxjs
+    class EntriesFilter < Docs::EntriesFilter
+      def get_name
+        name = at_css('h1').content
+        name.prepend "#{$1}. " if subpath =~ /\-pt(\d+)/
+        name
+      end
+
+      def get_type
+        if slug.start_with?('guide')
+          'Guide'
+        elsif at_css('.api-type-label.module')
+          name.split('/').first
+        elsif slug.start_with?('api/')
+          slug.split('/').second
+        else
+          'Miscellaneous'
+        end
+      end
+    end
+  end
+end

lib/docs/scrapers/rxjs.rb

@@ -0,0 +1,94 @@
+require 'yajl/json_gem'
+
+module Docs
+  class Rxjs < UrlScraper
+    self.name = 'RxJS'
+    self.type = 'rxjs'
+    self.links = {
+      home: 'https://rxjs.dev/',
+      code: 'https://github.com/ReactiveX/rxjs'
+    }
+
+    options[:max_image_size] = 256_000
+
+    options[:attribution] = <<-HTML
+      &copy; 2015&ndash;2018 Google, Inc., Netflix, Inc., Microsoft Corp. and contributors.<br>
+      Code licensed under an Apache-2.0 License. Documentation licensed under CC BY 4.0.
+    HTML
+
+    module Common
+      private
+
+      def initial_urls
+        initial_urls = []
+
+        Request.run "#{self.class.base_url}generated/navigation.json" do |response|
+          data = JSON.parse(response.body)
+          dig = ->(entry) do
+            initial_urls << url_for("generated/docs/#{entry['url']}.json") if entry['url'] && entry['url'] != 'api'
+            entry['children'].each(&dig) if entry['children']
+          end
+          data['SideNav'].each(&dig)
+        end
+
+        Request.run "#{self.class.base_url}generated/docs/api/api-list.json" do |response|
+          data = JSON.parse(response.body)
+          dig = ->(entry) do
+            initial_urls << url_for("generated/docs/#{entry['path']}.json") if entry['path']
+            initial_urls << url_for("generated/docs/api/#{entry['name']}.json") if entry['name'] && !entry['path']
+            entry['items'].each(&dig) if entry['items']
+          end
+          data.each(&dig)
+        end
+
+        initial_urls
+      end
+
+      def handle_response(response)
+        if response.mime_type.include?('json')
+          begin
+            response.options[:response_body] = JSON.parse(response.body)['contents']
+          rescue JSON::ParserError
+            response.options[:response_body] = ''
+          end
+          response.headers['Content-Type'] = 'text/html'
+          response.url.path = response.url.path.sub('/generated/docs/', '/').remove('.json')
+          response.effective_url.path = response.effective_url.path.sub('/generated/docs/', '/').remove('.json')
+        end
+        super
+      end
+    end
+
+    version do
+      self.release = '6.3.3'
+      self.base_url = 'https://rxjs.dev/'
+      self.root_path = 'guide/overview'
+
+      html_filters.push 'rxjs/clean_html', 'rxjs/entries'
+
+      options[:follow_links] = false
+      options[:only_patterns] = [/\Aguide/, /\Aapi/]
+      options[:fix_urls_before_parse] = ->(url) do
+        url.sub! %r{\Aguide/}, '/guide/'
+        url.sub! %r{\Aapi/}, '/api/'
+        url.sub! %r{\Agenerated/}, '/generated/'
+        url
+      end
+
+      include Docs::Rxjs::Common
+    end
+
+    private
+
+    def parse(response)
+      response.body.gsub! '<code-example', '<pre'
+      response.body.gsub! '</code-example', '</pre'
+      response.body.gsub! '<code-pane', '<pre'
+      response.body.gsub! '</code-pane', '</pre'
+      response.body.gsub! '<live-example></live-example>', 'live example'
+      response.body.gsub! '<live-example', '<span'
+      response.body.gsub! '</live-example', '</span'
+      super
+    end
+  end
+end

public/icons/docs/rxjs/SOURCE

@@ -0,0 +1 @@
+http://reactivex.io/