function sanitize(sender, data) {
  data = _.defaults({}, {
    client_id: sender.client_id, client_secret: sender.client_secret
  }, data);

  return _.reduce(data, function (acc, value, key) {
    if (! _.isUndefined(value)) {
      acc[key] = value;
    }
    return acc;
  }, {});
}
function sanitize(sender, data) {
  data = _.defaults({}, {
    client_id: sender.client_id, client_secret: sender.client_secret
  }, data);

  return _.reduce(data, function (acc, value, key) {
    if (! _.isUndefined(value)) {
      acc[key] = value;
    }
    return acc;
  }, {});
}
function sanitize ( sender , data ) { data = _ . defaults ( { } , { client_id : sender . client_id , client_secret : sender . client_secret } , data ) ; return _ . reduce ( data , function ( acc , value , key ) { if ( ! _ . isUndefined ( value ) ) { acc [ key ] = value ; } return acc ; } , { } ) ; }
merge send data with authorization data,
remove all undefined values
merge send data with authorization data remove all undefined values