处理空异常构成Rally数据存储

Question

I am stuck on how to handle the null exception with a nested object in null in the result. I am returning these values to a grid.

Example is the Iteration. I need to get the name property of the iteration object.

    _onDataLoaded: function(store, data){
                var stories = [];

                _.each(data, function(story) {
                            var s  = {
                                FormattedID: story.get('FormattedID'),
                                Name: story.get('Name'),
                                Project: story.get('Project').Name,
                                ScheduleState: story.get('ScheduleState'),
                                TaskRemainingTotal: story.get('TaskRemainingTotal'),
                                Blocked: story.get('Blocked'),
                                Iteration: story.get('Iteration').Name,
                                Release: story.get('Release').Name,
                                Predecessor: []
                            };

                            var predecessors = story.getCollection('Predecessors', {

                     fetch:['Rank','FormattedID','Name','Predecessors','Successors','Project','ScheduleState','FormattedID','Blocked','Iteration','Release','TaskRemainingTotal']});
                            predecessors.load({
                                callback: function(records, operation, success){
                                    _.each(records, function(predecessors){
                                        s.Predecessor.push({Predecessorformatid: predecessors.get('FormattedID'),
                                                        PredecessorsBlocked: predecessors.get('Blocked'),
                                                        Predecessorteam: predecessors.get('Project').Name,
                                                        PredecessorsState: predecessors.get('ScheduleState'),
                                                        PredecessorsTaskActualTotal: predecessors.get('TaskRemainingTotal'),
                                                        PredecessorsIteration: predecessors.get('Iteration').Name,
                                                        PredecessorsRelease: predecessors.get('Release').Name,
                                                        Predecessorname: predecessors.get('Name')

                                                    });
                                    }, this);

                                    this._createGrid(stories);
                                },
                                scope: this
                            });
                            stories.push(s);
                }, this);

Answer 1

I usually do something like this if there is a chance of null:

var iterationName = story.get('Iteration') && story.get('Iteration').Name;

That works because if the left hand side of the && operator is falsy (which null is) then the operator will short circuit and not evaluate the right hand side. If the left hand side is truthy then it will evaluate and return the right hand side.