[рони]

NovichokJS,

const user = {
  name: 'Alex',
  age: 32,
  offer() {
    console.log(`${this.name} have invited`);
  },
};

function getProperties(obj) {
  return Object.keys(obj).filter(prop => typeof obj[prop] !== 'function');
}

console.log(getProperties(user));