Ho un problema con HTTP in angolare.
Voglio solo GET
un JSON
elenco e mostrarlo nella vista.
Classe di servizio
import {Injectable} from "angular2/core";
import {Hall} from "./hall";
import {Http} from "angular2/http";
@Injectable()
export class HallService {
public http:Http;
public static PATH:string = 'app/backend/'
constructor(http:Http) {
this.http=http;
}
getHalls() {
return this.http.get(HallService.PATH + 'hall.json').map((res:Response) => res.json());
}
}
E nel HallListComponent
chiamo il getHalls
metodo dal servizio:
export class HallListComponent implements OnInit {
public halls:Hall[];
public _selectedId:number;
constructor(private _router:Router,
private _routeParams:RouteParams,
private _service:HallService) {
this._selectedId = +_routeParams.get('id');
}
ngOnInit() {
this._service.getHalls().subscribe((halls:Hall[])=>{
this.halls=halls;
});
}
}
Tuttavia, ho ottenuto un'eccezione:
TypeError: this.http.get (...). Map non è una funzione in [null]
hall-center.component
import {Component} from "angular2/core";
import {RouterOutlet} from "angular2/router";
import {HallService} from "./hall.service";
import {RouteConfig} from "angular2/router";
import {HallListComponent} from "./hall-list.component";
import {HallDetailComponent} from "./hall-detail.component";
@Component({
template:`
<h2>my app</h2>
<router-outlet></router-outlet>
`,
directives: [RouterOutlet],
providers: [HallService]
})
@RouteConfig([
{path: '/', name: 'HallCenter', component:HallListComponent, useAsDefault:true},
{path: '/hall-list', name: 'HallList', component:HallListComponent}
])
export class HallCenterComponent{}
app.component
import {Component} from 'angular2/core';
import {ROUTER_DIRECTIVES} from "angular2/router";
import {RouteConfig} from "angular2/router";
import {HallCenterComponent} from "./hall/hall-center.component";
@Component({
selector: 'my-app',
template: `
<h1>Examenopdracht Factory</h1>
<a [routerLink]="['HallCenter']">Hall overview</a>
<router-outlet></router-outlet>
`,
directives: [ROUTER_DIRECTIVES]
})
@RouteConfig([
{path: '/hall-center/...', name:'HallCenter',component:HallCenterComponent,useAsDefault:true}
])
export class AppComponent { }
tsconfig.json
{
"compilerOptions": {
"target": "ES5",
"module": "system",
"moduleResolution": "node",
"sourceMap": true,
"emitDecoratorMetadata": true,
"experimentalDecorators": true,
"removeComments": false,
"noImplicitAny": false
},
"exclude": [
"node_modules"
]
}
Http
servizio restituisce un osservabile
1.8.36
, mentre la guida di avvio rapido ng2 (mentre scrivo questo) sta usando "typescript": "^2.0.2"
. Aggiornamento del lang TS. il servizio tramite estensioni e aggiornamenti mi ha aiutato. Durante l'installazione dell'aggiornamento mi sono imbattuto in questa risposta SO , che termina con la stessa conclusione.