How to save POST to global variable in node - node.js

Question

I am sending json by POST to nodejs, I declared router.post in index.js, (/routes)
How I can save it so I can actually use that later on? Keep in mind that every 60sec I am getting new data that should replace the old one.
I am listening on port 3000
var express = require('express');
var router = express.Router();
var saveme
/* GET home page. */
router.get('/index', function(req, res, next) {
res.render('index', { title: 'RLH' });
});
router.post('/index', function(req, res, next) {
data = req.body;
console.log('OK')
});
module.exports = router;
I don't know how can I save what I get trough POST, so later on I can use it on my website.

Answer 1

There are multiple ways to use Global variable:
Method1
Using app.locals :
declare app.locals.data = {}; in main file (ex:server.js)
var app = express();
app.locals.data = {};
app.locals available to req object as req.app.locals. When you have new data you can update it as :
req.app.locals.data = req.body;
Method2
Using global object
Assign new data as global.data = req.body
You can always access data as global.data in same or different module
Method3(Recommended)
Create file globaldata.js with below code
module.exports = {};
Import globaldata.js where you need to access or update global data as
var globaldata = require('./globaldata.js');
globaldata = req.body;
What is recommended? global method for small apps, module.exports for big apps.
You can read below ref. for more details:
https://www.hacksparrow.com/nodejs/global-variables-in-node-js.html
http://expressjs.com/en/api.html#app.locals

Answer 2

If by saving the data you mean storing it in a variable you can do:
var express = require('express');
var router = express.Router();
var saveme;
/* GET home page. */
router.get('/index', function(req, res, next) {
if (saveme) {
// you can use `saveme`
res.render('index' + saveme.toString(), { title: 'RLH' });
}
else {
res.render('index', { title: 'RLH' });
}
});
router.post('/index', function(req, res, next) {
data = req.body;
// set `saveme`
saveme = data;
});
module.exports = router;