JSFiddle - React, Tailwind, and code Playground

by mach3ss

JavaScript

var getAge = function( dateString ){
    var a = new Date(), b = new Date( dateString );
    return a.getFullYear() - b.getFullYear() -
        Number( ! ( a.getMonth() > b.getMonth() && a.getDate() > b.getDate() ) );
};

document.write( getAge("1977/11/25") );