4 Bugs That Quietly Break Your App Without Crashing (How to Find Them) #Shorts #Debugging #Bugfender

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4 bugs that quietly break your app without crashing it, and how to find each one. No crash report, no error popup, just users who can't do what they came to do.

Each example follows the same beginner-friendly method: what the user sees, the evidence to check, and what to try next.

1. SAVE DOES NOTHING
2. What the user sees: they tap Save and nothing happens.
3. Check: your logs, the messages your app records as it runs. Look at what was logged around the tap.
4. Next step: if the save code never ran, check that the button is connected to it, e.g.
5. saveButton.addEventListener('click', savePreferences)
6. SAVED, BUT STALE
7. What the user sees: "Saved: Almond", but the screen still shows Oat.
8. Check: compare the value you saved with what the screen loaded.
9. Next step: if the screen used an old stored copy (a cache), refresh it after saving, e.g.
10. await savePreferences(prefs); cache.invalidate('preferences')
11. FAILS FOR SOME USERS
12. What the user sees: orders fail on some devices, but never on yours.
13. Check: open an affected device in Bugfender and read its logs and device details.
14. Next step: if a request failed, show the user a clear error instead of nothing, e.g.
15. if (!res.ok) showError("Couldn't place order")
16. ENDLESS SPINNER
17. What the user sees: the loading spinner never stops.
18. Check: log when the request starts and when it finishes.
19. Next step: if it never finishes, add a timeout (a time limit) and an error message, e.g.
20. fetch(url, { signal: AbortSignal.timeout(10000) })

WHY THESE BUGS ARE HARD
Crash reporting only sees crashes. These bugs leave the app running, so the evidence is in the logs and the device context: what the app did, on which device, just before the user gave up.

ABOUT THIS VIDEO
The app (Northstar Coffee) is fictional, the logs are synthetic and the code is illustrative. The Bugfender device-log view for bug 3 is a recreated demo session with a fictional Samsung Galaxy S24 device.