JSFiddle - React, Tailwind, and code Playground

JavaScript

var dob = 587001600;
// Monday, 8 August 1988 00:00:00

var todayInMilli = Math.round(new Date()/1000);
var ageInMilli = todayInMilli - dob;

var age = ageInMilli / (60 * 60 * 24 * 365);

document.write("dob: " + dob + "<br/>");
document.write("age: " + Math.floor(age) + "<br/>");