const user = {
  name: 'Sarah',
  age: 25,
  greet() {
    return `Hello, I'm ${this.name}`;
  }
};

const keys = Object.keys(user);
const values = Object.values(user);
const entries = Object.entries(user);

console.log(keys.length);
console.log(values.includes('Sarah'));
console.log(entries[2][0]);