04. Extensible Object

function extensibleObject() {
  const obj = {};
  obj.extend = function (template) {
    for (const prop in template) {
      if (typeof template[prop] === 'function') {
        Object.getPrototypeOf(obj)[prop] = template[prop];
      } else {
        obj[prop] = template[prop];
      }
    }
  };
  return obj;
}