code: function getListingWatcher(subreddit, options) {
          options.listing = options.listing || 'hot'
          subreddit = subreddit ? 'r/' + subreddit : ''
          let start_page = 'https://reddit.com/' + subreddit + '/'
          if (options.listing === 'hot' || options.listing === 'rising' || options.listing === 'controversial') {
              start_page += options.listing + '.json'
          } else if (options.listing === 'top_day' || options.listing === 'top_hour' || options.listing === 'top_month'
              || options.listing === 'top_year' || options.listing === 'top_all') {
              start_page += 'top.json?sort=top&t=' + options.listing.substring(4, options.listing.length)
          } else {
              throw "invalid listing type"
          }
  
          console.log(start_page)
          return new RedditListingWatcher(start_page, 'item', options)
      }
docs: listings are reddit pages where posts can show pop in and out in no particular order or location as opposed to feeds which sequentially display new content listings: hot, rising, controversial, top_day, top_hour, top_week, top_month, top_year, top_all