using forkJoin rxjs 6

multiple-requests-rxjs6.ts

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import {IncidentsDTO} from './incidents.model';
import {Observable} from "rxjs/internal/Observable";
import {forkJoin} from 'rxjs';
import {catchError} from "rxjs/operators";

@Injectable({
  providedIn: 'root'
})
export class SomeService {

  constructor(private http: HttpClient) { }

  public multipleRequests (data): Observable<any> {
    const reqObservables = data
      .map(id => this.http.patch(`api/${id}`, {something: "0"})
        .pipe(catchError(err => {
            return Observable.create({error: err});
        })));
    return forkJoin(reqObservables);
  }
}