Symfony 3, "ajax request" with fetch API, and CSRF - ajax

Question

In twig i generate a csrf token ({{ csrf_token('my_intention') }}).
In Javascript i call a controller with ajax, in fact with the Fetch API (Ajax xmlHttpRequest tried too), POST request. Argument name containing the token passed in the request is 'token=abcdef...'.
AJAX:
var httpRequest = new XMLHttpRequest();
httpRequest.onreadystatechange = function (data) {
console.log(data);
};
httpRequest.open('POST', el.getAttribute("data-url"));
httpRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
httpRequest.send(.......);
Fetch API:
fetch(el.getAttribute('data-url'), {
method: 'post',
headers: {
"Content-type": "application/x-www-form-urlencoded; charset=UTF-8"
},
body: 'token=' + encodeURIComponent(el.getAttribute('data-token'))
}).then(data => data.text()).then(data => {...}
In the controller action called i get the token sent as data from the POST request. I check the token like this in the controller:
$token = $request->request->get('token');
if (!$this->isCsrfTokenValid('my_intention', $token)) {
throw new InvalidCsrfTokenException("error csrf 2");
}
But Symfony say the token is not valid.
I'm not sure but i think token is not found in session variable. In isTokenValid() $this->storage->hasToken($token->getId()) return false.
In the browser, if i call the url directly, it's ok.
In twig i set the url to call in a data attribute like this data-url="{{ path('_check', {'id': transaction.id}) }}", then i read this data attribute from javascript and pass it to ajax/fetch function.
I tried ajax with jQuery $.post(... and it works. The only difference is Cookie:PHPSESSID... in the request header with jQuery not on my original code.
I don't understand, what is wrong with my code ?
Symfony 3.1.3
EDIT: resolved: i didn't pass credentials in headers request, so, no way for Symfony to find session and check token:
fetch(el.getAttribute('data-url'), {
method: 'post',
headers: {
"Content-Type": "application/x-www-form-urlencoded; charset=UTF-8",
"X-Requested-With": "XMLHttpRequest"
},
body: 'token=' + el.getAttribute('data-token'),
credentials: 'include'
}).then(data => data.text()).then(data => {

Answer 1

Even if you found an answer to your issue, I recommend you to take a look at this bundle which handles the token verification based on a Cookie which is defined server-side and that you should pass in each asynchronous request.
https://github.com/dunglas/DunglasAngularCsrfBundle