Which task was not immediately easy, and required some effort?

One of the tasks that was not immediately easy was related to optimizing the rendering of a large list of items in React. Initially, the page was very slow due to the large number of components, which worsened the user experience. It was necessary to understand list virtualization techniques, such as using the react-window library, to render only visible items. This significantly improved the performance and responsiveness of the interface.

Example of using react-window:

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

const Row = ({ index, style }) => (
  <div style={style}>Item #{index}</div>
);

<List
  height={150}
  itemCount={1000}
  itemSize={35}
  width={300}
>
  {Row}
</List>

This approach helped to handle the task and improve UX.