send URL parameters to Express with Angular 2 - express

Question

I'm using this Angular service to get data from Express:
getRestaurants(districtId) : Observable<void[]>{
let params: URLSearchParams = new URLSearchParams();
params.set('id', districtId);
return this.http.get(this.url, { search: params })
.map((res:Response) => res.json())
.catch((error:any) => Observable.throw(error.json().error || 'Server error'));
}
I was using this URL http://localhost:5050/api/district/restaurants?id=8
It works fine if in Express I use req.query But I need to use this new URL http://localhost:5050/api/district/:id/restaurants and use req.params in Express.
My problem is that I can't set the :id parameter using Angular without modifying the URL string and I suppose that there is a better way to do this task. Thanks for your help

Answer 1

What about this:
private url = 'http://localhost:5050/api/district/:id/restaurants';
private _prepareUrl(districtId: number): string {
return this.url.replace(':id', districtId);
}
getRestaurants(districtId) {
// ...
this.http.get(this._prepareUrl(districtId), ...);
// ...
}
You could use the Router's function createUrlTree, but you will have a prepare-function too..
private urlPrefix = 'http://localhost:5050/api';
constructor(private _router: Router) { }
private _prepareUrl(districtId: number): string {
return this.urlPrefix + this._router.createUrlTree(['district', districtId, 'restaurants']).toString();
}
getRestaurants(districtId) {
// ...
this.http.get(this._prepareUrl(districtId), ...);
// ...
}