There is a list of 5000 products on the page, and the page lags heavily. The business asks to do something about it. What would you suggest?

To optimize a page with a list of 5000 products and eliminate lags, the following approaches can be suggested:

1. Pagination or lazy loading — load and display products in portions, for example, 50-100 items, loading new ones when scrolling (infinite scroll) or switching pages.

2. List virtualization (windowing) — display only the elements visible to the user in the DOM, and do not render the rest. This significantly reduces the load on the browser.

3. Rendering optimization — use memoization of components, avoid unnecessary re-renders, apply React.memo, shouldComponentUpdate, or similar mechanisms.

4. Data optimization — minimize the size of transmitted data, use compression, caching.

5. Asynchronous image loading (lazy loading) — load images only when they appear in the viewport.

Example of using virtualization with React and the react-window library:

import { FixedSizeList as List } from 'react-window';

const Row = ({ index, style, data }) => (
  <div style={style}>
    {data[index].name}
  </div>
);

const ProductList = ({ products }) => (
  <List
    height={600}
    itemCount={products.length}
    itemSize={35}
    width={300}
    itemData={products}
  >
    {Row}
  </List>
);

This approach allows efficient handling of large lists without lag.