crud.service.ts

import { HttpClient } from '@angular/common/http';
import { Resolve, ActivatedRouteSnapshot } from '@angular/router';
import { first, Observable } from 'rxjs';

export abstract class CRUDService<T, C, U extends { id: string }> implements Resolve<T> {
  constructor(protected http: HttpClient, protected base: string) {
    console.log(`Instantiating ${this.base.slice(0, -1)} service`);
  }

  public findAll(): Observable<T[]> {
    return this.http.get<T[]>('/api/v1/' + this.base);
  }

  public findById(id: string): Observable<T> {
    return this.http.get<T>('/api/v1/' + this.base + '/' + id);
  }

  public create(params: C): Observable<T> {
    return this.http.post<T>('/api/v1/' + this.base, params);
  }

  public update({ id, ...params }: U): Observable<T> {
    return this.http.put<T>('/api/v1/' + this.base + '/' + id, params);
  }

  public delete(id: string): Observable<number> {
    return this.http.delete<number>('/api/v1/' + this.base + '/' + id);
  }

  public resolve(route: ActivatedRouteSnapshot): Observable<T> {
    const id = route.paramMap.get('id');

    console.log(`Resolving ${this.base.slice(0, -1)} ${id}`);

    if (!id) {
      throw new Error(`Missing param "id" to resolve ${this.base.slice(0, -1)}`);
    }

    return this.findById(id).pipe(first());
  }
}