You can get headers using below code
let main_headers = {}
this.http.post(url,
{email: this.username, password: this.password},
{'headers' : new HttpHeaders ({'Content-Type' : 'application/json'}), 'responseType': 'text', observe:'response'})
.subscribe(response => {
const keys = response.headers.keys();
let headers = keys.map(key => {
`${key}: ${response.headers.get(key)}`
main_headers[key] = response.headers.get(key)
}
);
});
later we can get the required header form the json object.
header_list['X-Token']