const planetsOrderFromSun = new Set();

planetsOrderFromSun.add('Mercury');

planetsOrderFromSun.add('Venus').add('Earth').add('Mars');

console.log(planetsOrderFromSun.has('Earth'));

​

planetsOrderFromSun.delete('Mars');

console.log(planetsOrderFromSun.has('Mars'));

​

for (const planet of planetsOrderFromSun) {

  console.log(planet);

}

console.log(planetsOrderFromSun.size);

​

planetsOrderFromSun.add('Venus');

console.log(planetsOrderFromSun.size);

​

planetsOrderFromSun.clear();

console.log(planetsOrderFromSun.size);