Vue-i18n + ruby i18n-tasks unused scanner

vue_i18n_scanner.rb

require 'i18n/tasks/scanners/file_scanner'

# finds v-t="" and $t/$tc usages and prefixed that usages with the given prefix, e.g.
# so i18n-tasks unused / i18n-tasks missing will work and scan vue files correctly
# LIMITATIONS: 
#  - no advanced v-t="{ ... }" syntax supported
#  - of course, no dynamic loading of $t(some_data_property) does not work
class VueI18nScanner < I18n::Tasks::Scanners::FileScanner
  include I18n::Tasks::Scanners::OccurrenceFromPosition

  KEY_IN_QUOTES = /(?<in>["'])(?<key>[\w\.]+)(?<in>["'])/.freeze
  WRAPPED_KEY_IN_QUOTES = /(?<out>["'])#{KEY_IN_QUOTES}(?<out>["'])/.freeze

  # @return [Array<[absolute key, Results::Occurrence]>]
  def scan_file(path)
    text = read_file(path)
    # single file component translation used
    return [] if text.include?('<i18n')

    out = []
    # v-t="'key'"  v-t='"key"'
    text.to_enum(:scan, /v-t=#{WRAPPED_KEY_IN_QUOTES}/).each do |_|
      key = Regexp.last_match[:key]
      occurrence = occurrence_from_position(
        path, text, Regexp.last_match.offset(:key).first
      )
      out << [key, occurrence]
    end
    text.to_enum(:scan, /\$tc?\(#{KEY_IN_QUOTES}/).each do |_|
      key = Regexp.last_match[:key]
      occurrence = occurrence_from_position(
        path, text, Regexp.last_match.offset(:key).first
      )
      out << [key, occurrence]
    end
    out
  end
end
I18n::Tasks.add_scanner 'VueI18nScanner', only: %w(*.vue *.js)