factory.getRelatedTags produces JS error when no items found

[lazd]

At the following URL: http://readup.co/#/pinky

TypeError: Cannot read property 'length' of undefined
    at http://readup.co/build/bundle.js:682:40
    at http://readup.co/lib/bower_components/angular/angular.js:9137:11
    at wrappedCallback (http://readup.co/lib/bower_components/angular/angular.js:6995:59)
    at http://readup.co/lib/bower_components/angular/angular.js:7032:26
    at Object.Scope.$eval (http://readup.co/lib/bower_components/angular/angular.js:8218:28)
    at Object.Scope.$digest (http://readup.co/lib/bower_components/angular/angular.js:8077:25)
    at Object.Scope.$apply (http://readup.co/lib/bower_components/angular/angular.js:8304:24)
    at done (http://readup.co/lib/bower_components/angular/angular.js:9357:20)
    at completeRequest (http://readup.co/lib/bower_components/angular/angular.js:9520:7)
    at XMLHttpRequest.xhr.onreadystatechange (http://readup.co/lib/bower_components/angular/angular.js:9490:11) angular.js:5930

It's happening in this method:

  factory.getRelatedTags = function(tagName){
    var deferred = $q.defer();
    var requestURL = '/_/tags/' + tagName + '/items/1';
    $http.get(requestURL).success(function(data){
      var results = {};
      for(var i = 0; i < data.length; i++){
        for(var j = 0; j < data[i].tags.length; j++){
          if(data[i].tags[j].name !== tagName){
            results[data[i].tags[j].name] = data[i].tags[j].name;
          }
        }
      }
      deferred.resolve(results);
    });
    return deferred.promise;
  };

At the time of execution, data was:

[{"title":"No items found."}]

Since the object doesn't have a tags property, accessing tags.length fails and the promise is rejected. Check for the presence of tags before attempting to iterate over them.