cache with rs

ng2-cache.js

getFiles(idinfosys, idcategorie){
    //when this http request is cached and not old more than 3sec
   if(Date.now() > this.cachedData[idcategorie].time+3){
      let rs = new ReplaySubject<any>(1);
      rs.next(this.cachedData[idcategorie].data);
      return rs;
    }
    // https request isn't cached
    return this.http.get(this.SERVER_URL+'dms/list/categories?idinfosys='+idinfosys+'&idcategorie='+idcategorie+'&alf_ticket='+this.TICKET).map((data : Response) => {
      // cache this http request
      this.cachedData[idcategorie] = {data: data.json(), time: Date.now()}
      return data.json()
    })
  }