function one(selector, el) {
  return el.querySelector(selector);
}

exports = module.exports = function(selector, el){
  el = el || document;
  return one(selector, el);
};

exports.all = function(selector, el){
  el = el || document;
  return el.querySelectorAll(selector);
};

exports.engine = function(obj){
  if (!obj.one) throw new Error('.one callback required');
  if (!obj.all) throw new Error('.all callback required');
  one = obj.one;
  exports.all = obj.all;
  return exports;
};