[frontend] Timer leaks: 145 setTimeout/setInterval with only 42 matching clears #797

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opened 2026-06-03 00:42:57 +02:00 by sleepy · 0 comments

sleepy commented

2026-06-03 00:42:57 +02:00

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Finding

Across the largest JS files, timers are created far more often than they are cleared:

File	setTimeout/setInterval	clearTimeout/clearInterval	Delta
chat.js	29	25	4
document.js	42	20	22
sessions.js	19	9	10
settings.js	25	3	22
notes.js	33	10	23
emailLibrary.js	26	4	22

Total: 174 timers created, only 71 cleared — 103 potentially leaked timers.

Impact

Orphaned intervals run forever (e.g., research polling at line 3901 runs setInterval every 2s, only cleared on specific conditions)
Orphaned timeouts fire on destroyed DOM elements or stale closures
Memory cannot be reclaimed because closures retain references to large objects
Particularly problematic for long-lived SPA pages where the user may be active for hours

Recommendation

Track all timer IDs per module and clear them on teardown
Use AbortController to cancel both fetch and timers atomically
Guard all timer callbacks with DOM existence checks before acting

## Finding Across the largest JS files, timers are created far more often than they are cleared: | File | setTimeout/setInterval | clearTimeout/clearInterval | Delta | |------|----------------------|---------------------------|-------| | chat.js | 29 | 25 | 4 | | document.js | 42 | 20 | **22** | | sessions.js | 19 | 9 | **10** | | settings.js | 25 | 3 | **22** | | notes.js | 33 | 10 | **23** | | emailLibrary.js | 26 | 4 | **22** | **Total: 174 timers created, only 71 cleared — 103 potentially leaked timers.** ## Impact - Orphaned intervals run forever (e.g., research polling at line 3901 runs `setInterval` every 2s, only cleared on specific conditions) - Orphaned timeouts fire on destroyed DOM elements or stale closures - Memory cannot be reclaimed because closures retain references to large objects - Particularly problematic for long-lived SPA pages where the user may be active for hours ## Recommendation 1. Track all timer IDs per module and clear them on teardown 2. Use AbortController to cancel both fetch and timers atomically 3. Guard all timer callbacks with DOM existence checks before acting