javascript中是否存在null-coalescing(Elvis)运算符或安全导航运算符？

const value = null;
const result = value || 'default';
console.log(result); // 输出 'default'

const result2 = value ? value : 'default';
console.log(result2); // 输出 'default'

const user = {
  name: 'John',
  address: {
    city: 'New York'
  }
};

const city = user?.address?.city;
console.log(city); // 输出 'New York'

const nonExistent = user?.nonExistent?.property;
console.log(nonExistent); // 输出 undefined