My class currently looks like this:

```
export class Patient {
    constructor(public id: number, public name: string, public location: string, public bedId: number, public severity: string,
                public trajectory: number, public vitalSigns: [GraphData[]], public latestReading: GraphData[]) {
    }

    public get combinedVSData(): Array<GraphData> {
        let combinedVitalSigns: GraphData[] = [];
        for (let data of this.vitalSigns) {
            combinedVitalSigns.push(data[0]);
        }
        return combinedVitalSigns;
    }
}

```

When I try to call `patient.combinedVSData`, it says it returns `undefined`. I've tried to simply make it return a string with the same result, and I've made console.log()'s in the method but i don't see anything in the console, so it doesn't get called at all. What am I doing wrong?

I'm calling the method in one of my templates like so:

```
 [results]="patientService.patientLevel3.combinedVSData"

```

I'm also calling it in one of my components' class just to test it:

```
onDrop(event: any){
let movedPatient: Patient = JSON.parse(event.dataTransfer.getData("patient"));
let from = parseInt(event.dataTransfer.getData("from"));

console.log(movedPatient.combinedVSData);

this.patientService.patientLevel3 = movedPatient;
this.patientService.removePatient(from, movedPatient.id);
}

}

```

Both cases it's undefined. 

EDIT: I've found out that the reason combinedVSData is not on the object is because it apparently loses it when it gets converted to JSON. I don't know what can be done about it though.