20 new API endpoints

src/routes/api/math/factorial.js

@@ -0,0 +1,23 @@
+const express = require('express');
+const router = express.Router();
+
+function factorial(n) {
+    if (n === 0 || n === 1) return 1;
+    let result = 1;
+    for (let i = 2; i <= n; i++) result *= i;
+    return result;
+}
+
+router.post('/', (req, res) => {
+    const n = Math.floor(Number(req.body.input));
+    if (n < 0 || n > 170) return res.status(400).json({ error: 'n must be between 0 and 170' });
+    res.json({ ret: factorial(n) });
+});
+
+router.get('/:n', (req, res) => {
+    const n = Math.floor(Number(req.params.n));
+    if (n < 0 || n > 170) return res.status(400).json({ error: 'n must be between 0 and 170' });
+    res.json({ ret: factorial(n) });
+});
+
+module.exports = router;