Base Rest Service for angular

RestService.ts

import { Headers, RequestOptionsArgs, Response, Request } from '@angular/http';
import { Observable } from 'rxjs/Observable';

interface IRestConfig {
    baseHeaders?: Headers;
    baseUrl: string;
    path?: string;
}

interface IRestQuery {
    [key: string]: boolean | number | string;
}

interface IRestConfig {
  apiBaseUrl: string,
  endPoint: string,
}


interface IHttp {
  delete: (url: string, options?: RequestOptionsArgs) => Observable<Response>;
  get: (url: string, options?: RequestOptionsArgs) => Observable<Response>;
  head: (url: string, options?: RequestOptionsArgs) => Observable<Response>;
  patch: (url: string, body: any, options?: RequestOptionsArgs) => Observable<Response>;
  post: (url: string, body: any, options?: RequestOptionsArgs) => Observable<Response>;
  put: (url: string, body: any, options?: RequestOptionsArgs) => Observable<Response>;
  request: (url: string | Request, options?: RequestOptionsArgs) => Observable<Response>;
}


export abstract class BaseRestService {
  private _base: string;
  private _path: string;
  protected http: IHttp;

  constructor(http: IHttp, config: IRestConfig) {
    this._base = config.apiBaseUrl.replace(/\/$/, '');
    this._path = config.path.replace(/^\//, '');
    this._path = config.path;
    this.http = http;
  }

  public save(obj: any): Observable<any> {
    if (!!obj.id) {
      const url = this.buildUrl(obj.id);
      return this.http.put(url, obj).map(r => r.json());
    } else {
      const url = this.buildUrl();
      return this.http.post(url, obj).map(r => r.json());
    }
  }

  protected buildUrl(id?: number | string): string {
    let url: string = (this._path) ? `${this._path}/` : '';
    url = (id) ? `${url}${id}/` : '';
    url = `${this._base}/${url}`;
    return url;
  }
}