プロキシの力

const user = {
  name: 'Zain',
  age: 22
};

const handler = {
  get: (target, prop) => {
    console.log(`Getting property ${prop}`);
    return prop in target ? target[prop] : 'Property does not exist';
  },
  set: (target, prop, value) => {
    if (prop === 'age' && typeof value !== 'number') {
      console.log('Invalid age type. It should be a number.');
    } else {
      console.log(`Setting property ${prop} to ${value}`);
      target[prop] = value;
    }
    return true;
  }
};

const proxiedUser = new Proxy(user, handler);

console.log(proxiedUser.name); // Logs: Getting property name
proxiedUser.age = 'twenty-two'; // Logs: Invalid age type. It should be a number.
proxiedUser.age = 23; // Logs: Setting property age to 23