JSFiddle - React, Tailwind, and code Playground

JavaScript

var date1 = new Date();
    var date2 = new Date();
    date2.setFullYear(
        date1.getFullYear(),
        date1.getMonth()+3,
        date1.getDate()+25
    )
    date2.setHours(
        date1.getHours()+5,
        date1.getMinutes()+20,
        date1.getSeconds()+ 19
    )
    
    var d = date1.getTime();
    var s = date2.getTime();

    var year = Math.abs(date1.getFullYear() - date2.getFullYear())+ ' лет '
    var month = Math.floor((Math.abs(d-s)/1000/3600/24/30) % 12 ) + ' месяцев ';
    var day = Math.floor((Math.abs(d-s)/1000/3600/24) % 30  ) +' дней ';
    
    var hour = Math.abs(Math.floor(((d-s)/1000/3600)) % 24) +' часов '
    var minut = Math.abs(Math.floor(((d-s)/60000)) % 60) +' минут '
    var second = Math.abs(Math.floor(((d-s)/1000)) % 1000) + ' секунд'
    document.writeln(date1.toLocaleString() + " <br />");
    document.writeln(date2.toLocaleString() + " <br />");    
document.writeln(year + month  + day +' '+ hour+ minut + second )