JSFiddle - React, Tailwind, and code Playground

JavaScript

function isValidDate(year, month, day) {
    var d = new Date(parseInt(year,10), parseInt(month, 10)-1, parseInt(day, 10), 0, 0, 0);
    return d.getFullYear() == year &&
           (d.getMonth()+1) == month &&
           d.getDate() == day;
}
            
document.write(isValidDate("2011", "08", "04") + "<br/>");
document.write(isValidDate("bob", "08", "04") + "<br/>");
document.write(isValidDate("1979", "1", "1"));