Handle startup errors and harden notes loading

Gruntfile.js

@@ -0,0 +1,57 @@
+module.exports = function (grunt) {
+  const { spawn, spawnSync } = require('child_process');
+  const fs = require('fs');
+  const path = require('path');
+
+  grunt.registerTask('syntax', 'Check JavaScript syntax', () => {
+    const result = spawnSync(process.execPath, ['--check', 'index.js'], {
+      cwd: __dirname,
+      encoding: 'utf8'
+    });
+
+    if (result.status !== 0) {
+      grunt.log.error(result.stderr || result.stdout);
+      return false;
+    }
+
+    grunt.log.ok('index.js syntax check passed.');
+  });
+
+  grunt.registerTask('validate-json', 'Validate project JSON files', () => {
+    ['haikus.json', 'notes.json', 'process.json'].forEach((fileName) => {
+      const filePath = path.join(__dirname, fileName);
+      const content = fs.readFileSync(filePath, 'utf8');
+      JSON.parse(content);
+      grunt.log.ok(`${fileName} is valid JSON.`);
+    });
+  });
+
+  grunt.registerTask('check', ['syntax', 'validate-json']);
+
+  grunt.registerTask('start-app', 'Start the app process', function () {
+    const done = this.async();
+    const appProcess = spawn('npm', ['start'], {
+      cwd: __dirname,
+      stdio: 'inherit',
+      shell: true
+    });
+
+    const shutdown = () => {
+      if (!appProcess.killed) {
+        appProcess.kill('SIGTERM');
+      }
+    };
+
+    process.on('SIGINT', shutdown);
+    process.on('SIGTERM', shutdown);
+
+    appProcess.on('exit', (code) => {
+      process.off('SIGINT', shutdown);
+      process.off('SIGTERM', shutdown);
+      done(code === 0);
+    });
+  });
+
+  grunt.registerTask('serve', ['check', 'start-app']);
+  grunt.registerTask('default', ['check']);
+};

README.md

@@ -8,3 +8,13 @@ This is a quick node project template for demoing Codespaces. It is based on the
 This sample now includes a simple notes application. Visit `/notes` to create and view notes stored in `notes.json`.
 
 Point your browser to [Quickstart for GitHub Codespaces](https://docs.github.com/en/codespaces/getting-started/quickstart) for a tour of using Codespaces with this repo.
+
+## Build/Check Tooling
+
+This project now includes a lightweight Grunt setup for local checks:
+
+- `npm run check`: Run JavaScript syntax checks and JSON validation.
+- `npm run check:json`: Validate JSON files only.
+- `npm run start:checked`: Run checks, then start the app.
+
+If Grunt commands are missing in your environment, run `npm install` in the project root to install all dependencies from `package-lock.json`.

index.js

@@ -16,7 +16,8 @@ const notesPath = path.join(__dirname, 'notes.json');
 function loadNotes() {
   try {
     const data = fs.readFileSync(notesPath, 'utf8');
-    notes = JSON.parse(data);
+    const parsedNotes = JSON.parse(data);
+    notes = Array.isArray(parsedNotes) ? parsedNotes : [];
   } catch (err) {
     notes = [];
   }
@@ -48,7 +49,15 @@ app.post('/notes', (req, res) => {
   res.redirect('/notes');
 });
 
-app.listen(port, () => {
+const server = app.listen(port, () => {
   console.log(`Server running on port ${port}`);
 });
 
+server.on('error', (err) => {
+  if (err.code === 'EADDRINUSE') {
+    console.error(`Port ${port} is already in use. Please stop the existing process or set a different PORT.`);
+    process.exit(1);
+  }
+
+  throw err;
+});