Help needed , angular post , PHP mysql

I am using angular 4 , php mysql.

i am sending a post to php mysql from angular.

i want to get the response of the php json as you see in the code below , to the angular , to know , whether the data has been submitted or not .

My Angular Script 

import { Injectable } from '@angular/core';  
import { Http,  Response ,RequestOptions,Headers} from '@angular/http';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/map'

@Injectable()
export class appService {  
     
    postResponse:any ;
    status;
    constructor(private http:Http) { }
 
   insertData() {
    let headers = new Headers({ 'Content-Type': 'application/json' });
    let options = new RequestOptions({ headers: headers });
    return this.http.post('http://localhost:80/angularsql/sql.php',JSON.stringify({firstName:'Joe',lastName:'Smith333'}),{headers:headers})
    .map((res: Response) => res.json())
    .subscribe((res:'') => this.postResponse = res);
   }
}

My php Script :

<?php 
header("Access-Control-Allow-Origin: *");
header("Access-Control-Allow-Methods: PUT, GET, POST");
header("Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept");
$data = json_decode( file_get_contents('php://input'),true );
  $fname =  $data['firstName'];
  $lname =  $data['lastName'];
 
$con = new mysqli('localhost','root','','angular');
if($fname=='anan' && $lname=='kassis') {
$sql = "insert into users_tbl(firstName,lastName) values('".$fname."','".$lname."')";
$result = $con->query($sql);
	$data = [ "status" => "details inserted" ];
echo json_encode($data);
}
else {
	$data = [ "status" => "didn't insert details" ];
echo json_encode($data);
}
?>