Api call to json to interface to Mat-Tree - json

Question

I'm running into issues with trying to convert a json response from an Api call into an interface that will be accepted by this buildFileTree. So the call is pulling from SQL, it is working in dapper, I also see the array of data in my webapp in my console. The issue is when I try to change the initialize() value for buildFileTree from my static json file 'SampleJson' (inside the project) to my new interface 'VehicleCatalogMod' the tree shows up with SampleJson but when I switch the data to VehicleCatalogMod, the tree collapses.
dataStoreNew: VehicleCatalogMod[] = [];
constructor(private _servicesService: ServicesService){
this._servicesService.GetVehicleCat()
.subscribe(data => {
this.dataStoreNew = [];
this.dataStoreNew = data;
console.log(data);
})
this.initialize();
}
initialize() {
this.treeData = SampleJson;
// Working as SampleJson this is where the problem happens
const data = this.buildFileTree(VehicleCatalogMod, 0);
console.log(data);
this.dataChange.next(data);
}
buildFileTree(obj: object, level: number): TodoItemNode[] {
return Object.keys(obj).reduce<TodoItemNode[]>((accumulator, key) => {
let value = obj[key];
const node = new TodoItemNode();
node.item = key;
if (value != null) {
if (typeof value === 'object') {
node.children = this.buildFileTree(value, level + 1);
} else {
node.item = value;
}
}
return accumulator.concat(node);
}, []);
}
GetVehicleCat(): Observable<any> {
console.log('Vehicle Catalog got called');
return this.http.get('https://api/right/here',
{ headers: this.options.headers });
}
I tried a multitude of different things to try & get this working. I'm pretty much stagnated. Same error occurs when I try this.dataStoreNew instead. No errors in console, it literally just collapses the tree into one non distinguishable line. Also when I used: const vcm = new VehicleCatalogMod(); it made the tree pop up with the different properties but not the API values.
I also attached an image of the HTML element that appears.
with VehicleCatalogMod
with SampleJson