从PHP后端仅返回JSON

Hi guys i'm using Angular 4 for my front end to return json from backend but instead of pure json data it return me more, how can i return only json? Is the problem in the backend or should i do something in the front end?

I'm using codeigniter in the backend this inside the method:

$this->FAM->list_app();

from the model this already implementing json_encode()

and from the model backend:

$arrayindex=array();

foreach($query->result_array() as $r){
    $arrayindex[] = $r;
}

echo json_encode($arrayindex);

You can do this on the frontEnd service by using res.json() and then access the body of it,

   yourService(): Observable<any> {
        return this._http.get('url')
        .map(this.success)
        .catch(this.fail);
    }

    private success(res: Response) {
        if (!res || res.status !== 200) {
            return [];
        }
        const data = res.json();
        const results = data ? (data.message ? data.message : []) : [];
        //return results;
          return data;
    }

    private fail(error: Response | any) {
        let errMsg: string;
        if (error instanceof Response) {
            const body = error.json() || '';
            const err = body.error || JSON.stringify(body);
            errMsg = `${error.status} - ${error.statusText || ''} ${err}`;
        } else {
            errMsg = error.message ? error.message : error.toString();
        }
        console.error(errMsg);
        return Observable.throw(errMsg);
    }