03. Inbox Manager js exam

function solve(args) {
  const users = {};
  let inputLine = args.shift();

  while (inputLine !== 'Statistics') {
    const [command, userName, email] = inputLine.split('->');


    switch (command) {
      case 'Add':
        if (!Object.prototype.hasOwnProperty.call(users, userName)) {
          const emails = [];
          users[userName] = { emails };
        } else {
          console.log(`${userName} is already registered`);
        }
        break;
      case 'Send':
        users[userName].emails.push(email);
        break;
      case 'Delete':
        if (Object.prototype.hasOwnProperty.call(users, userName)) {
          delete users[userName];
        } else {
          console.log(`${userName} not found!`);
        }
        break;
      default:
        break;
    }


    inputLine = args.shift();
  }

  console.log(`Users count: ${Object.keys(users).length}`);
  Object.entries(users)
    .sort((a, b) => b[1].emails.length - a[1].emails.length || a[0].localeCompare(b[0]))
    .forEach((el) => {
      const [name, arg1] = el;

      console.log(`${name}`);
      arg1.emails.forEach((email) => {
        console.log(` - ${email}`);
      });
    });
}