fix: resolve ESLint unused vars and jest globals errors

Author: ManmathX

backend/eslint.config.mjs

@@ -2,7 +2,7 @@ import globals from 'globals';
 import pluginJs from '@eslint/js';
 
 export default [
-  { languageOptions: { globals: globals.node } },
+  { languageOptions: { globals: { ...globals.node, ...globals.jest } } },
   pluginJs.configs.recommended,
   {
     rules: {

backend/src/app.js

@@ -12,7 +12,7 @@ app.get('/api/products', (req, res) => {
   try {
     const products = db.prepare('SELECT * FROM products').all();
     res.json(products);
-  } catch (err) {
+  } catch {
     res.status(500).json({ error: 'Failed to fetch products' });
   }
 });
@@ -36,7 +36,7 @@ app.post('/api/checkout', (req, res) => {
 
     // Simulate order success
     res.json({ message: 'Checkout successful', total, orderId: Date.now() });
-  } catch (err) {
+  } catch {
     res.status(500).json({ error: 'Checkout failed' });
   }
 });

backend/tests/db.test.js

@@ -1,5 +1,3 @@
-const Database = require('better-sqlite3');
-
 describe('Database Module', () => {
   let db;