[x ] bug report => search github for a similar issue or PR before submitting
[ ] feature request
[ ] support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question

let body = new URLSearchParams();

for (let i in values) {
    body.set(i, values[i]);
}

let options = RequestOptions();
options.headers.append('Content-Type', 'application/x-www-form-urlencoded')
return this.http.post(uri, body, options).then();
[...]