JSFiddle - React, Tailwind, and code Playground

by Andrés Leone

HTML

<span class="datetime">2013-01-27 10:34:13</span><br/>
<span class="datetime">2014-05-05 23:22:24</span><br/>
<span class="datetime">2014-01-01 00:00:00</span><br/>
<span class="datetime">2013-12-31 00:00:00</span><br/>
<span class="datetime">2013-12-31 23:59:59</span>

JavaScript

utc2local=function(b,c){void 0===b.length&&(b=[b]);void 0===c&&(c=function(a){return a.getFullYear()+"-"+(a.getMonth()+1)+"-"+a.getDate()+" "+a.getHours()+":"+a.getMinutes()+":"+a.getSeconds()});for(var d=0;d<b.length;){var a=b[d].innerHTML.trim(),a=a.split(" ");utc_date=a[0].split("-");utc_time=a[1].split(":");var e=a=new Date(utc_date[0],+utc_date[1]-1,utc_date[2],utc_time[0],utc_time[1],utc_time[2],0);e.setMinutes(a.getMinutes()-a.getTimezoneOffset());b[d++].innerHTML=c(e)}};

utc2local(document.querySelectorAll('.datetime'), function(date){
        return date.getDate() + ' ' + ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec'][date.getMonth()] +' at ' + date.getHours() + ' hours, ' + date.getMinutes() + ' minutes.';
    });