flare-json.service.ts

@Injectable()
export class FlareJsonService implements HierarchicalData {

  private d3: D3;

  constructor(private http: Http, d3Service: D3Service, private url: string) {
    this.d3 = d3Service.getD3();
  }

  getRoot(): Observable<HierarchyNode<any>> {
    return this.http.get('./assets/' + this.url).map(res => {
      const rawData = res['_body'] || '';
      let parsedJson = JSON.parse(rawData);
      return this.d3.hierarchy(parsedJson)
        .sum((d: HierarchyPointNode<any>) => (<any>d).size)
        .sort((a, b) => (<any>b).value - (<any>a).value);
    });
  }
}