code: function(criteria) {
            var results = [];
  
            criteria = angular.isArray(criteria) ? criteria : [criteria];
  
            // Search through each
            criteria.forEach(function(q) {
              if(q && q !== '') {
  
                _listing.forEach(function(item) {
                  for(var name in item) {
                    if(item[name].toLowerCase().indexOf(q.toLowerCase()) !== -1 && results.indexOf(item) === -1) {
                      results.push(item);
                    }
                  }
                });
              }
            });
  
            return $q.when(results);
          }
docs: Search for a product