The Confused Timezone
Events show the correct date to the person who created them, but other users in different timezones see the same event listed one day earlier or one day later.
The bug report
You get the whole project — a React front end, an Express API, and Mongoose models — opened in a browser editor. Reproduce the symptom by reading the code, change what’s wrong, and run the hidden tests to prove it.
What the fix must prove
- stores the chosen day as a UTC timestamp
- renders the same calendar day in every timezone
- returns the submitted day on read-back
- rejects impossible calendar days
- lists events in calendar order
Related challenges
- The Missing Name — api contract bug, beginner
- The Ghost Update — async / race condition, intermediate
- The Silent Field — database / schema bug, beginner