Rails I18n Exception Handler

custom_i18n_exception_handler.rb

### CUSTOM I18N EXCEPTION HANDLER
### 1. This exception handler enforces that an exception is raised whenever a translation is not found rather than showing "translation missing" to user

### 2. YOU CAN USE I18n.t(key, fallback: true) and it will now handle missing translations as follows:
###
###    If a specific key is used ie. 'fisheries.locations.asd' and the translation is not found then it will look for:
###     - 'common.asd'
###

module I18n
  class CustomExceptionHandler < ExceptionHandler
    def call(exception, locale, key, options)
      if exception.is_a?(MissingTranslation) && key.to_s != 'i18n.plural.rule'
        if options[:fallback]
          generic_key = "common.#{key.to_s.split(".").last}"
          alt_key = nil
          # if key.to_s.include?("_form.")
          #   alt_key = key.to_s.split(".")[-2..-1].join(".")
          # end
          if I18n.exists?(generic_key)
            return I18n.t(generic_key, fallback: false)
          elsif alt_key && I18n.exists?(alt_key)
            return I18n.t(alt_key, fallback: false)
          else
            raise exception.to_exception
          end
        else
          raise exception.to_exception
        end
      else
        super
      end
    end
  end
end
I18n.exception_handler = I18n::CustomExceptionHandler.new