JSFiddle - React, Tailwind, and code Playground

HTML

<h3>device id:<span id="deviceid"></span></h3>

JavaScript

uuid=function(){
var u = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g,
function(c) {
var r = Math.random() * 16 | 0,
v = c == 'x' ? r : (r & 0x3 | 0x8);
return v.toString(16);
});
return u;
}


getDeviceId = function(){
var current = window.localStorage.getItem("_DEVICEID_")
if (current) return current;
var id = uuid();
window.localStorage.setItem("_DEVICEID_",id);   
return id;
}

document.getElementById("deviceid").innerHTML=getDeviceId();