JSFiddle - React, Tailwind, and code Playground

HTML

<pre></pre>

JavaScript

function FormattedDate() {
    var args = Array.prototype.concat.apply([null], arguments);
    var days = [ "Sunday", "Monday", "Tuesday", "Wednesday", 
                     "Thursday", "Friday", "Saturday" ];
    
    var months = ["January", "Feburary", "March", "April", "May", "June", "July", 
                     "August", "September", "October", "November", "December"];
    
    this.date = this.now = new (Function.prototype.bind.apply(Date, args));
    
    this.day = this.days = this.date.getDate()+1;
    this.dayName = this.dayname = this.day_name = days[this.date.getDay()-1];
    this.dayShort = this.dayshort = this.day_short = this.dayName.slice(0,3);
    
    this.month = this.months = this.mo = this.mos = this.date.getMonth()+1;
    this.monthName = this.monthname = this.month_name = months[this.month-1];
    this.monthShort = this.monthshort = this.month_short = this.monthName.slice(0,3);
    
    this.year = this.years = this.yr = this.yrs = this.date.getFullYear();
    
    this.hour = this.hours = this.hr = this.hrs = this.date.getHours();
    this.minute = this.minutes = this.min = this.date.getMinutes();
    this.second = this.seconds = this.sec = this.secs = this.date.getSeconds();
    
    this.millisecond = this.milliseconds = this.ms = this.date.getMilliseconds();
    
    this.time = this.epoch = this.date.getTime();

    this.today  = !!(new Date(new Date()-(24*60*60*1000)) < this.date);
}

FormattedDate.prototype = {
    stringify: function stringify(entity, format) {
        format = format || "MM/DD/YY HH:mm:ss";
        
        if (entity) {
            if (typeof this[entity] === 'string') return this[entity];
            
            if (entity !== 'date') {
                var num = this[entity];
                if (num < 10) return "0"+num;
                return ""+num;
            }
        }
        
        if (this.today) {
            var now = new FormattedDate();
            var hoursAgo = (now.hour - this.hour);
         ...