brew/Library/Homebrew/livecheck/strategy/npm.rb

# typed: false
# frozen_string_literal: true

module Homebrew
  module Livecheck
    module Strategy
      # The {Npm} strategy identifies versions of software at
      # registry.npmjs.org by checking the listed versions for a package.
      #
      # npm URLs take one of the following formats:
      #
      # * `https://registry.npmjs.org/example/-/example-1.2.3.tgz`
      # * `https://registry.npmjs.org/@example/example/-/example-1.2.3.tgz`
      #
      # The default regex matches URLs in the `href` attributes of version tags
      # on the "Versions" tab of the package page.
      #
      # @api public
      class Npm
        NICE_NAME = "npm"

        # The `Regexp` used to determine if the strategy applies to the URL.
        URL_MATCH_REGEX = %r{
          ^https?://registry\.npmjs\.org
          /(?<package_name>.+?)/-/ # The npm package name
        }ix.freeze

        # Whether the strategy can be applied to the provided URL.
        #
        # @param url [String] the URL to match against
        # @return [Boolean]
        def self.match?(url)
          URL_MATCH_REGEX.match?(url)
        end

        # Generates a URL and regex (if one isn't provided) and passes them
        # to {PageMatch.find_versions} to identify versions in the content.
        #
        # @param url [String] the URL of the content to check
        # @param regex [Regexp] a regex used for matching versions in content
        # @return [Hash]
        def self.find_versions(url, regex = nil, &block)
          match = url.match(URL_MATCH_REGEX)

          page_url = "https://www.npmjs.com/package/#{match[:package_name]}?activeTab=versions"

          # Example regexes:
          # * `%r{href=.*?/package/example/v/(\d+(?:\.\d+)+)"}i`
          # * `%r{href=.*?/package/@example/example/v/(\d+(?:\.\d+)+)"}i`
          regex ||= %r{href=.*?/package/#{Regexp.escape(match[:package_name])}/v/(\d+(?:\.\d+)+)"}i

          PageMatch.find_versions(page_url, regex, &block)
        end
      end
    end
  end
end