refactor: refactor sanitizeFilename utility that ensures valid file names

calendar/test.ics

@@ -0,0 +1,46 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//sebbo.net//ical-generator//EN
+NAME:test
+X-WR-CALNAME:test
+BEGIN:VEVENT
+UID:881z@Ryan-jr
+SEQUENCE:0
+DTSTAMP:20241107T111355Z
+DTSTART:20240930T113000Z
+DTEND:20240930T123000Z
+SUMMARY:work other work
+END:VEVENT
+BEGIN:VEVENT
+UID:lhyi@Ryan-jr
+SEQUENCE:0
+DTSTAMP:20241107T111355Z
+DTSTART:20241003T190000Z
+DTEND:20241003T200000Z
+SUMMARY:work progodessey
+END:VEVENT
+BEGIN:VEVENT
+UID:5l54@Ryan-jr
+SEQUENCE:0
+DTSTAMP:20241107T111355Z
+DTSTART:20241009T173000Z
+DTEND:20241009T183000Z
+SUMMARY:work do
+END:VEVENT
+BEGIN:VEVENT
+UID:cp96@Ryan-jr
+SEQUENCE:0
+DTSTAMP:20241107T111355Z
+DTSTART:20241001T183000Z
+DTEND:20241001T193000Z
+SUMMARY:Other work calmerge
+END:VEVENT
+BEGIN:VEVENT
+UID:jxsj@Ryan-jr
+SEQUENCE:0
+DTSTAMP:20241107T111355Z
+DTSTART:20241010T173000Z
+DTEND:20241010T183000Z
+SUMMARY:Other work to do
+END:VEVENT
+END:VCALENDAR

calendar/test.json

@@ -0,0 +1,15 @@
+{
+  "linkGroupName": "test",
+  "calendars": [
+    {
+      "prefix": "work",
+      "override": false,
+      "url": "https://calendar.google.com/calendar/ical/b4c66eb4bb2cc15257d071bab3f935385778b042112ea1aaedada47f3f1a6e3a%40group.calendar.google.com/public/basic.ics"
+    },
+    {
+      "prefix": "Other work",
+      "override": false,
+      "url": "https://calendar.google.com/calendar/ical/774518759e4e2dd42aab0c511b02397bb216f3b67dc425d76bae07d1eff529d6%40group.calendar.google.com/public/basic.ics"
+    }
+  ]
+}

server.js

@@ -18,10 +18,8 @@ fs.mkdirSync(MERGED_CALENDARS_DIR, { recursive: true });
 app.get('/script.js', (req, res) => res.sendFile('script.js', { root: '.' }));
 app.get('/', (req, res) => res.sendFile('index.html', { root: '.' }));
 
-// Function to sanitize the linkGroupName for use as a filename
-function sanitizeFilename(filename) {
-    return filename.replace(/[<>:"/\\|?* ]/g, '_'); // Replace invalid characters with underscores
-}
+// Utility to sanitize filenames
+const sanitizeFilename = (filename) => filename.replace(/[<>:"/\\|?* ]/g, '_');
 
 // Merge calendars endpoint
 app.post('/merge', async (req, res) => {