06.js

const response3 = [
  { purchaseId: 21, productName: 'Bag' },
  { purchaseId: 22, productName: 'Lamp' },
];

const requiredOutput3 = [
  { productId: 31, purchaseId: 21, product: { name: 'Bag' } },
  { productId: 32, purchaseId: 22, product: { name: 'Lamp' } },
];