var qs = require('qs');
var user = { username: 'someUser', password: 'somePassword' };
$http.post(`${API_URL}/login`, qs.stringify(user), {
  headers: { 'Content-Type': 'application/x-www-form-urlencoded' }
});

var user = { username: 'someUser', password: 'somePassword' };
$http.post(`${API_URL}/login`, user);

Content-Type: application/json