app.js

/*eslint no-console: ["error", { allow: ["log","warn", "error"] }] */
const path = require('path');

const state = {
	server: null,
	sockets: []
};

function start(){
	state.server = require('./server')().listen(3000,() => {
		console.log('Started on 3000');
	});
	state.server.on('connection',(socket) => {
		console.log('Add socket',state.sockets.length + 1);
		state.sockets.push(socket);
	});
}

function pathCheck(id){
	return (
		id.startsWith(path.join(__dirname,'routes')) ||
    id.startsWith(path.join(__dirname,'server.js'))
	);
}

function restart(){
	//clean the cache
	Object.keys(require.cache).forEach((id) => {
		if (pathCheck(id)){
			console.log('Reloading',id);
			delete require.cache[id];
		}
	});

	state.sockets.forEach((socket,index) => {
		console.log('Destroying socket',index + 1);
		if (socket.destroyed === false){
			socket.destroy();
		}
	});

	state.sockets = [];

	state.server.close(() => {
		console.log('Server is closed');
		console.log('\n----------------- restarting -------------');
		start();
	});
}

start();

const chokidar = require('chokidar');
chokidar.watch(['./routes','./server.js']).on('all',(event,at) => {
	if (event === 'add'){
		console.log('Watching for',at);
	}

	if (event === 'change'){
		console.log('Changes at',at);
		restart();
	}
});