import { ReportHandler } from 'web-vitals'; type FuncType = (onPerfEntry?: ReportHandler) => void; const reportWebVitals: FuncType = (onPerfEntry?: ReportHandler) => { if (onPerfEntry !== null && onPerfEntry instanceof Function) { void import('web-vitals').then(({ getCLS, getFID, getFCP, getLCP, getTTFB }) => { getCLS(onPerfEntry); getFID(onPerfEntry); getFCP(onPerfEntry); getLCP(onPerfEntry); getTTFB(onPerfEntry); }); } }; export default reportWebVitals;