JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://github.com/douglascrockford/JSON-js/raw/master/json2.js"></script>

JavaScript

// JSON received from server is in string format
var s = '1293034567877';
var jsonString = '{"date": 1293034567877}';

//use JSON2 or some JS library to parse the string
var jsonObject =  JSON.parse( jsonString );

//now you have your date!
alert( new Date(jsonObject.date));