add template

src/app/demo/service/countryservice.ts

@@ -0,0 +1,15 @@
+import { HttpClient } from '@angular/common/http';
+import { Injectable } from '@angular/core';
+
+@Injectable()
+export class CountryService {
+
+    constructor(private http: HttpClient) { }
+
+    getCountries() {
+    return this.http.get<any>('assets/demo/data/countries.json')
+      .toPromise()
+      .then(res => res.data as any[])
+      .then(data => data);
+    }
+}