Angular 4.4.4  

This is my app component

```
constructor(
    private http: HttpClient,
)

this.http.post('/api.php', {name, age}).subscribe(data => {
    console.log(data);
});

```

`api.php -> exit(json_encode($_POST));`

Don't receive any data in $\_POST

return [];

(`let xmlRequest = new XMLHttpRequest();`
....
 works fine)

I try set header 

```
  let headers = new HttpHeaders().set('Content-Type', 'application/json; charset=UTF-8');

```

not work

Sorry for this question but I spent 1 day and still could not find solution.

ps. client and server has same origin.