Question du test Angular 4 (legacy)

Que fait le code suivant ?

import {Service} from '@angular/core';
import {Http}    from '@angular/http';
import {Issue}   from './issue';

@Injectable()
export class HeroService {
    constructor(private http: Http) {
    }

    getList(): Promise<Issue[]> {
        return this.http.get('/issues/')
            .toPromise()
            .then((response) => {
                return response.json() as Issue[];
            })
            .catch(this.handleError);
    }

    private handleError(error: any): Promise<any> {
        console.error('An error occurred', error);
        return Promise.reject(error.message || error);
    }
}