Dasherized Rails routes

route_format.rb

# config/initializers/route_format.rb
#
# Global route formatting override for Rails routing.
#
# This hooks into ActionDispatch::Routing::Mapper::Mapping and mutates the
# Journey AST in place so that underscored literal path segments are
# dasherized. It affects *all* routes (get, resources, scope, etc.)
# because they all end up as a Journey AST passed into Mapping.
#
# IMPORTANT:
#   - This does NOT distinguish between symbols and strings in the routes DSL.
#   - Any literal segment like "linked_in" becomes "linked-in".
#   - Dynamic params (e.g. :id) are not changed.
#

Rails.application.config.routes_format = :dasherize

module RouteFormatAstRewrite
  private

  # Recursively walk a Journey AST node and rewrite literal segments in-place.
  #
  # Only touches ActionDispatch::Journey::Nodes::Literal instances whose
  # underlying string contains an underscore. Other node types are left as-is.
  def rf_rewrite_ast(node)
    formatter = Rails.application.config.routes_format
    return unless formatter
    return unless node

    case node
    when ActionDispatch::Journey::Nodes::Literal
      value = node.left
      if value.is_a?(String) && value.include?("_")
        node.left = value.public_send(formatter)
        # Clear cached to_s so Journey will recompute the string
        node.instance_variable_set(:@to_s, nil)
      end

    when ActionDispatch::Journey::Nodes::Binary
      rf_rewrite_ast(node.left)
      rf_rewrite_ast(node.right)

    when ActionDispatch::Journey::Nodes::Unary,
         ActionDispatch::Journey::Nodes::Group,
         ActionDispatch::Journey::Nodes::Star
      rf_rewrite_ast(node.left)

    when ActionDispatch::Journey::Nodes::Or
      node.children.each { |child| rf_rewrite_ast(child) }

    else
      # leave other node types unchanged
    end
  end

  # Hook into Mapping initialization to rewrite the AST before the
  # Journey::Path::Pattern is built.
  def initialize(*, ast:, **, &)
    rf_rewrite_ast(ast)

    super(*, ast:, **, &)
  end
end

# Patch the core Mapping class used by all router macros.
ActionDispatch::Routing::Mapper::Mapping.prepend(RouteFormatAstRewrite)