start and stop a loop with rest api call

const express = require('express');
const bodyParser = require('body-parser');
process.env.dataFeed = 'off';
process.env.intervalObject = null;
var app = express();
const port = 3000;
app.use(bodyParser.json());
app.get('/on', (req, res) => {
 let dataFeedStatus = process.env.dataFeed;
 if (dataFeedStatus === 'off') {
 process.env.dataFeed = 'on';
 res.send('process started');
 process.env.intervalObject = setInterval(() =>{
 console.log('running');
 }, 5000);
 } else if (dataFeedStatus === 'on') {
 res.send('already running');
 }
 
});
app.get('/off', (req, res) => {
 let dataFeedStatus = process.env.dataFeed;
 if (dataFeedStatus === 'on') {
 process.env.dataFeed = 'off';
 if (process.env.intervalObject != null) {
 clearInterval(process.env.intervalObject);
 process.env.intervalObject = null;
 }
 res.send('process stopped');
 } else if(dataFeedStatus === 'off') {
 res.send('process is already off')
 }
});
app.listen(port, () => {
 console.log(`Started up at port ${port}`);
});
module.exports = {app};