Class: ERBLint::Linters::GitHub::Accessibility::AvoidGenericLinkText

Inherits:
Linter
  • Object
show all
Includes:
CustomHelpers, LinterRegistry
Defined in:
lib/erblint-github/linters/github/accessibility/avoid_generic_link_text.rb

Constant Summary collapse

BANNED_GENERIC_TEXT = 
[
  "Read more",
  "Learn more",
  "Click here",
  "More",
  "Link",
  "Here"
].freeze
ARIA_LABEL_ATTRIBUTES = 
%w[aria-labelledby aria-label].freeze
MESSAGE = 
"Avoid using generic link text such as #{BANNED_GENERIC_TEXT.join(', ')} which do not make sense in isolation."

Constants included from CustomHelpers

CustomHelpers::INTERACTIVE_ELEMENTS

Instance Method Summary collapse

Methods included from CustomHelpers

#basic_conditional_code_check, #counter_correct?, #focusable?, #generate_offense, #generate_offense_from_source_range, #possible_attribute_values, #simple_class_name, #tags

Instance Method Details

#run(processed_source) ⇒ Object 



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# File 'lib/erblint-github/linters/github/accessibility/avoid_generic_link_text.rb', line 25

def run(processed_source)
  processed_source.ast.children.each_with_index do |node, index|
    next unless node.methods.include?(:type) && node.type == :text

    text = node.children.join.strip

    # Checks HTML tags
    if banned_text?(text)
      prev_node = processed_source.ast.children[index - 1]
      next_node = processed_source.ast.children[index + 1]

      next unless tag_type?(prev_node) && tag_type?(next_node)

      text_node_tag = BetterHtml::Tree::Tag.from_node(node)
      prev_node_tag = BetterHtml::Tree::Tag.from_node(prev_node)
      next_node_tag = BetterHtml::Tree::Tag.from_node(next_node)

      aria_label = possible_attribute_values(prev_node_tag, "aria-label")
      aria_labelledby = possible_attribute_values(prev_node_tag, "aria-labelledby")

      # Checks if nested between two link tags.
      if link_tag?(prev_node_tag) && link_tag?(next_node_tag) && next_node_tag.closing?
        # Skip because we cannot reliably check accessible name from aria-labelledby, or an aria-label that is set to a variable
        # with static code analysis.
        next if aria_labelledby.present? || (aria_label.present? && aria_label.join.include?("<%="))
        # Skip because aria-label starts with visible text which we allow. Related to Success Criterion 2.5.3: Label in Name
        next if aria_label.present? && valid_accessible_name?(aria_label.join, text)

        range = prev_node_tag.loc.begin_pos...text_node_tag.loc.end_pos
        source_range = processed_source.to_source_range(range)
        generate_offense_from_source_range(self.class, source_range)
      end
    end

    # Checks Rails link helpers like `link_to`
    node.descendants(:erb).each do |erb_node|
      _, _, code_node = *erb_node
      source = code_node.loc.source
      ruby_node = extract_ruby_node(source)
      send_node = ruby_node&.descendants(:send)&.first
      next unless send_node.methods.include?(:method_name) && send_node.method_name == :link_to

      banned_text = nil

      send_node.child_nodes.each do |child_node|
        banned_text = child_node.children.join if child_node.methods.include?(:type) && child_node.type == :str && banned_text?(child_node.children.join)
        next if banned_text.blank?
        next unless child_node.methods.include?(:type) && child_node.type == :hash

        child_node.descendants(:pair).each do |pair_node|
          next unless pair_node.children.first.type?(:sym)

          # Skips if `link_to` has `aria-labelledby` or `aria-label` which cannot be evaluated accurately with ERB lint alone.
          # ERB lint removes Ruby string interpolation so the `aria-label` for "<%= link_to 'Learn more', "aria-label": "Learn #{@some_variable}" %>" will
          # only be `Learn` which is unreliable so we can't do checks :(
          key_value = pair_node.children.first.children.join
          banned_text = nil if ARIA_LABEL_ATTRIBUTES.include?(key_value)
          next unless key_value == "aria"

          pair_node.children[1].descendants(:sym).each do |sym_node|
            banned_text = nil if sym_node.children.join == "label" || sym_node.children.join == "labelledby"
          end
        end
      end
      if banned_text.present?
        tag = BetterHtml::Tree::Tag.from_node(code_node)
        generate_offense(self.class, processed_source, tag)
      end
      banned_text = nil
    end
  end
end