JSFiddle - React, Tailwind, and code Playground

JavaScript

var last_seen = new Date(2017, 12, 06, 9,45,00);
var now = new Date(2017, 12, 06, 10,46,00);

now.setHours(now.getHours()-1);


console.log("now ",now.getDay()+"/"+now.getMonth()+"/"+now.getFullYear(),now.getHours()+":"+now.getMinutes());
console.log("data time ",last_seen.getDay()+"/"+last_seen.getMonth()+"/"+last_seen.getFullYear(),last_seen.getHours()+":"+last_seen.getMinutes());
//console.log(new Date((last_seen.getTime()-now.getTime())).getTime() < (1000*60*60));


console.log(now.getTime()>last_seen.getTime())


//ng-class="{CLASSNAME: (now.getTime()>last_seen.getTime())}"