Developed a feature for the apify/crawlee repository that introduced the nestedSitemapFilter option to the parseSitemap function, enabling custom logic for filtering nested sitemap URLs. This enhancement allows for selective inclusion of child sitemaps, reducing the processing of irrelevant URLs and improving the relevance of crawl results for downstream analytics. The work involved full stack development using TypeScript, with a strong emphasis on code quality and reliability. Comprehensive tests were implemented to validate the new filtering behavior and guard against regressions, ensuring that the feature integrates smoothly into existing workflows and maintains the robustness of the sitemap parsing process.