angular2 services - How to download data from JSON file in angular 2 -

this component file response coming service file. want download file json records in it. code able download file in file not getting json data. displaying [object object].

export class mydrivecomponent implements oninit {     drivelists: any;    data: any;    constructor(private downloaddataservice : downloaddataservice) { }        ngoninit(){       downloadfile(){            console.log(this.data);            this.downloaddataservice.downloadfile().            subscribe(data => {this.data = json.stringify(data)},            err            => console.log(err),            ()             => this.download(this.data));          }        download(data)        {           console.log(data);           var blob = new blob([data], { type: 'text/csv' });           var url= window.url.createobjecturl(blob);           window.open(url);        }  } 

this service file

export class downloaddataservice {   constructor(private http: http){ }      result : any;      downloadfile()     {         return this.http.get('assets/json/download.json').map(response => response.json().downloaddata);     } }