Express static server with Read/Write json file

server.mjs

/**
 * Server side for issuance client scripts
 */

import path from "path";
import Express from 'express';
import BodyParser from "body-parser";

import { readFile, writeFile } from "./util";

const root = process.cwd();
const p = path.resolve(root, 'build');
const configFile = path.resolve(root, 'config/config.json');
const app = Express();

app.use(Express.static(p));
app.use(BodyParser.urlencoded({ extended: false }));
app.use(BodyParser.json());


app.get('/', (req, res) => {
	res.sendFile(`${p}/index.html`, {
		headers: {
			'Content-Type': 'text/html'
		}
	});
});

app.post('/active', async (req, res) => {
	const { active } = req.body;

	try {
		await writeFile(configFile, JSON.stringify({ active }));
	} catch (error) {
		throw error;
		res.status(500).send(error);
	}

	res.status(200).send('Ok');
});
app.get('/active', async (req, res) => {
	let active;

	try {
		active = JSON.parse(await readFile(configFile));
	} catch (error) {
		throw error;
		res.status(500).send(error);
	}

	res.status(200).send(active);
});


app.listen(process.env.PORT, (err) => {
	if (err) throw err;

	console.log(`Server is running on localhost:${process.env.PORT}`);
});

util.mjs

import fs from "fs";

const readFile = (path, options) => new Promise((resolve, reject) => {
	fs.readFile(path, options, (err, data) => {
		if (err) reject(err);

		resolve(data);
	});
});

const writeFile = (path, data, options) => new Promise((resolve, reject) => {
	fs.writeFile(path, data, options, (err) => {
		if (err) reject(err);

		resolve();
	});
});

export {
	readFile,
	writeFile
}