added nominatim.service.ts

src/app/app.component.ts

@@ -1,19 +1,14 @@
-import { Component, OnInit, AfterViewInit, NgModule } from '@angular/core';
+import { Component, OnInit, AfterViewInit } from '@angular/core';
+import { Nominatim } from './interfaces/nominatim';
+import { NominatimService } from './nominatim.service';
+
 import { defaults as defaultControls } from 'ol/control';
 import { fromLonLat } from 'ol/proj';
-import { Observable, throwError } from 'rxjs';
-import { map } from 'rxjs/operators';
-import { BrowserModule } from '@angular/platform-browser';
-import { HttpClient } from '@angular/common/http';
-
 import Map from 'ol/Map';
 import View from 'ol/View';
 import TileLayer from 'ol/layer/Tile';
 import XYZ from 'ol/source/XYZ';
 import ZoomToExtent from 'ol/control/ZoomToExtent';
-import { Nominatim } from './interfaces/nominatim';
-
-
 
 @Component({
   selector: 'app-root',
@@ -25,14 +20,14 @@ export class AppComponent implements AfterViewInit, OnInit {
   title = "Street Map";
   map: Map;
 
-
-  constructor(private http: HttpClient) { }
+  constructor(private nominatimService: NominatimService) { }
   
-
-  getValue(valueFrom:string, valueTo:string){
+  // Gets called in "app.component.html" when an input changes its value
+  getValue(valueFrom:string, valueTo:string): void{
     console.log("From " + valueFrom + " to " + valueTo);
-    this.http.get<Nominatim>("https://nominatim.openstreetmap.org/search.php?format=jsonv2&q=" + valueFrom)
-    .subscribe((response: Nominatim) => console.log(response))
+
+    this.nominatimService.sendQueryRequest(valueFrom)
+    .subscribe((response: Nominatim[]) => console.log(response));
   }
 
   ngOnInit() {

src/app/interfaces/nominatim.ts

@@ -1,4 +1,4 @@
-
+// Nominatim JSON object to TypeScript interface
 export interface Nominatim {
     boundingbox: Array<string>;
     category: string;

src/app/nominatim.service.spec.ts

@@ -0,0 +1,16 @@
+import { TestBed } from '@angular/core/testing';
+
+import { NominatimService } from './nominatim.service';
+
+describe('NominatimService', () => {
+  let service: NominatimService;
+
+  beforeEach(() => {
+    TestBed.configureTestingModule({});
+    service = TestBed.inject(NominatimService);
+  });
+
+  it('should be created', () => {
+    expect(service).toBeTruthy();
+  });
+});

src/app/nominatim.service.ts

@@ -0,0 +1,18 @@
+import { Injectable } from '@angular/core';
+import { HttpClient } from '@angular/common/http';
+import { Nominatim } from './interfaces/nominatim';
+import { Observable } from 'rxjs';
+
+@Injectable({
+  providedIn: 'root'
+})
+
+// communicates with Nominatim (https://nominatim.org/)
+export class NominatimService{
+  constructor(private http: HttpClient) { }
+
+  // sends a query request to Nominatim and gets response (https://nominatim.org/release-docs/develop/api/Search/)
+  sendQueryRequest(q: string): Observable<Nominatim[]> { 
+    return this.http.get<Nominatim[]>("https://nominatim.openstreetmap.org/search.php?format=jsonv2&q=" + q);
+  }
+}