Приведи пример задач по реализации бизнес логики

const validateForm = (formData) => {
  const { email, password } = formData;
  const errors = {};
  if (!email.includes('@')) errors.email = 'Invalid email';
  if (password.length < 8) errors.password = 'Password too short';
  return Object.keys(errors).length ? errors : null;
};

const filterProducts = (products, filters) => {
  return products.filter(product => {
    return (
      product.price >= filters.minPrice &&
      product.price <= filters.maxPrice &&
      (filters.category ? product.category === filters.category : true)
    );
  });
};

const fetchData = async () => {
  try {
    const response = await fetch('https://api.example.com/data');
    if (!response.ok) throw new Error('Network error');
    return await response.json();
  } catch (error) {
    console.error('Fetch failed:', error);
    return null;
  }
};