NodeJS: Files only update after restarting the express server - node.js

Question

I am using nodejs with express for a small backend application which just returns a json file from another directory.
Example scenario:
My json files are in the directory "/var/data", so e.g. "/var/data/hello.json". If I start the nodejs backend with "node index.js" everything works as expected.
But if I change the contents of a json file, I still get the old version from the backend.
How can I set this up, so that my backend nodejs server detects these file changes in another directory without restarting it?
index.js:
const express = require('express');
const fs = require('fs');
const app = express();
app.use(express.json());
const myDataPath = "/var/data/";
app.get("/:id", (request, response) => {
let id = request.params.id;
let path = myDataPath + id + ".json";
if (fs.existsSync(path)) {
response.json(require(path));
} else {
response.sendStatus(404);
}
});

Answer 1

Issue is likely with using "require", this is a guess, but maybe require doesn't run twice for optimization reasons.
const express = require('express');
const fs = require('fs');
const app = express();
app.use(express.json());
const myDataPath = './var/data/';
app.get('/:id', (request, response) => {
let id = request.params.id;
let path = myDataPath + id + '.json';
console.log(path);
if (fs.existsSync(path)) {
response.json(JSON.parse(fs.readFileSync(path)));
} else {
response.sendStatus(404);
}
});
app.listen(1025);
The above code snippet worked on my testing example, I used readFileSync to retrieve the data, uncached, and the response changes when the file is modified, without needing to restart the app.