Remove an account from a Stormpath group knowing only the account and group's href

nodemodule.js

  function _removeAccountFromGroup(account, group) {
    var href = new Buffer(group, 'base64').toString('utf8');

    function findByGroupId(membership, callback) {
      return callback(membership.group.href === href);
    }

    return Promise.fromNode(function(callback) {

      return account.getGroupMemberships(function(err, memberships) {

        if(err) {
          return callback(err);
        }

        return memberships.detect(findByGroupId, function(membership) {

          return membership.delete(function(err) {

            if(err) {
              return callback(err);
            }

            return callback();
          });
        });
      });
    });
  }