Optimized Data Transformation: Achieving O(N) Time Complexity

index.jsx

// The task is to implement generateOrderSummary function

const users = [
  { id: 1, name: 'Alice', age: 30 },
  { id: 2, name: 'Bob', age: 25 },
  { id: 3, name: 'Charlie', age: 35 }
];

const products = [
  { id: 101, name: 'Product A', price: 50 },
  { id: 102, name: 'Product B', price: 100 },
  { id: 103, name: 'Product C', price: 75 }
];

const orders = [
  { id: 1001, userId: 1, productId: 101, quantity: 2 },
  { id: 1002, userId: 2, productId: 102, quantity: 1 },
  { id: 1003, userId: 1, productId: 103, quantity: 3 }
];

const generateOrderSummary = ({ orders, products, users }) => {
	// TODO: it should generate summary for every order
  // so that response will look like this:
  //{
  //  orderId: 1001,
  //  user: { id: 1, name: 'Alice', age: 30 },
  //  product: { id: 101, name: 'Product A', price: 50 },
  //  total: 100 // price * quantity
  //}
 
  
	const userMap = new Map (users.map(user => [user.id, user]));
  const productMap = new Map (products.map(product => [product.id, product]));
  
  return orders.map((order) => {
  	const user = userMap.get(order.userId);
		const product = productMap.get(order.productId);
		const total = product.price * order.quantity;
		
    return {
   		orderId: order.id,
  		user: { id: user.id, name: user.name, age: user.age },
  		product: { id: product.id, name: product.name, price: product.price },
  		total: total
    };
  });
};

const Component = () => {
	const [body, setBody] = React.useState({});
  
  React.useEffect(() => {
    try {
      setBody(generateOrderSummary({ products, orders, users }))
    } catch (err) {
      console.log(err)
    }
  }, []);
  
	return (
  	<div className="container">
      <pre>{JSON.stringify(body, null, 2)}</pre>
  	</div>
  )
}

ReactDOM.createRoot(document.getElementById('app')).render(<Component />);