const dedupe = (): void => { const seen = new Set(); const elements = document.querySelectorAll('[data-id]'); elements.forEach(item => { const id = item.getAttribute('data-id'); if (!id) { return; } if (seen.has(id)) { item.remove(); } else { seen.add(id); } }); }; if (document.readyState === 'loading') { document.addEventListener('DOMContentLoaded', dedupe); } else { dedupe(); } window.addEventListener('load', dedupe); window.addEventListener('load', dedupe);