code: function unwatch(id) {
      let type = typeof id;
      let index = watchers.findIndex(function _matchWatcher(watcher) {
        return watcher && (type === 'string' ? watcher.id === id : watcher.callback === id);
      });
  
      if (index !== -1) {
        // We can't delete the last watcher...
        if (watchers.length === 1) {
          unwatchAll();
        } else {
          delete watchers[index];
        }
      }
    }
docs: Clear/remove specific watcher by id or callback function
  
  @param {String|Function} id - String id (returned from watch() or callback function)