How to get data from mockAPI

I want to get data when input username === responseApi.user from api but my code get all data user from api. Help me to get data tks u Here is a part of my code from service.ts

     @Injectable()
        export class AuthenticationService {
          private apiUrl = "http://5925399f21cf650011fddc7d.mockapi.io/api/users/";
          private users: any[]
          constructor(
            private _router: Router, private _http: Http) { }

      getList(): Observable<any[]> {
        return this._http.get(this.apiUrl).map((response: Response) => response.json())

      }
      logout() {
        localStorage.removeItem("user");
        this._router.navigate(['Login']);
      }

      login(user) {
    this._http.get(this.apiUrl).map((response: Response) => response.json()).subscribe((response: any) => {
    this.users = response;
      console.log(this.users)
      console.log(user.user)
      var authenticatedUser = this.users.find(u => u.user === user.user)
      var authenticatedUser1 = this.users.find(u => u.password === user.password);
      if (authenticatedUser && authenticatedUser1) {
        localStorage.setItem('user', authenticatedUser)
        this._router.navigate(['Home']);

        return true;
      }
      return false;
    }


    )


  }

via Bi Li