Upgrade to using ES modules, and assert LTS stable node

.nvmrc

@@ -0,0 +1 @@
+v22.15.0

index.js

@@ -1,13 +1,13 @@
-const express = require('express');
-const rateLimit = require('express-rate-limit');
-const fs = require('fs');
+import { readFile } from "node:fs/promises";
+import express from "express";
+import rateLimit from "express-rate-limit";
 
 const app = express();
 app.set('trust proxy', true);
 const PORT = process.env.PORT || 3000;
 
 // Load reasons from JSON
-const reasons = JSON.parse(fs.readFileSync('./reasons.json', 'utf-8'));
+const reasons = JSON.parse(await readFile('./reasons.json', 'utf-8'));
 
 // Rate limiter: 120 requests per minute per IP
 const limiter = rateLimit({

package.json

@@ -3,6 +3,7 @@
   "version": "1.0.0",
   "description": "A lightweight API that returns random rejection or no reasons.",
   "main": "index.js",
+  "type": "module",
   "scripts": {
     "start": "node index.js"
   },
@@ -11,5 +12,8 @@
   "dependencies": {
     "express": "^4.18.2",
     "express-rate-limit": "^7.0.0"
+  },
+  "engines": {
+    "node": ">=22.15.0"
   }
 }