code: function pageDefaults() {
    return {
      path: canonicalPath(),
      referrer: document.referrer,
      search: location.search,
      title: document.title,
      url: canonicalUrl(location.search)
    };
  }
docs: Return a default `options.context.page` object.
  
  https://segment.com/docs/spec/page/#properties
  
  @return {Object}