type ReportHandler = (...args: unknown[]) => void; const reportWebVitals = (onPerfEntry?: ReportHandler) => { if (onPerfEntry && onPerfEntry instanceof Function) { import('web-vitals').then(({ onCLS, onINP, onFCP, onLCP, onTTFB }) => { onCLS(onPerfEntry); onINP(onPerfEntry); onFCP(onPerfEntry); onLCP(onPerfEntry); onTTFB(onPerfEntry); }); } }; export default reportWebVitals;