javascript vypočítať čas
console.time("timer"); //start time with name = timer
console.timeEnd("timer"); //end timer and log time difference
javascript rozdiel medzi dvoma dátumami v dňoch
const diffDays = (date, otherDate) => Math.ceil(Math.abs(date - otherDate) / (1000 * 60 * 60 * 24));
// Example
diffDays(new Date('2014-12-19'), new Date('2020-01-01')); // 1839