text: let urgentTasks = ['Buy three tickets'];
  let normalTasks = ['Book a hotel', 'Rent a car'];
  let allTasks = [...urgentTasks, ...normalTasks];
  
  // Spread tasks to a list of parameters
  ((first, second, third, fourth) => {
    console.log('Working on ' + first + ' and ' + second + ' and ' + third + ' and ' + fourth)
  })(...allTasks);
  
  
  let hotel = {name: 'Hotel A', city: {name: 'Sanya'}};
  let price = {price: 100};
  // Merge objects only with shallow clone
  let booking = {...hotel, ...price};
  console.log(booking); // {name: "Hotel A", price: 100, city : {name: 'Sanya'}}
  hotel.city.name = 'Xiamen';
  console.log(booking.city.name); // Xiamen