[frontend] Event listener leaks: 2,225 addEventListener vs 242 removeEventListener #791

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opened 2026-06-03 00:40:12 +02:00 by sleepy · 0 comments

sleepy commented

2026-06-03 00:40:12 +02:00

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Finding

Frontend JS has 2,225 addEventListener calls but only 242 removeEventListener calls — a 9:1 ratio indicating systematic listener leaks. Worst offenders:

File	addEventListener	removeEventListener
document.js	211	21
chat.js	30	0
notes.js	144	8
settings.js	157	3
emailLibrary.js	111	13
slashCommands.js	57	54

Impact

chat.js has zero cleanup — every listener added is permanent
notes.js leaks 136 listeners (144 added, 8 removed)
settings.js leaks 154 listeners
Over time, switching sessions, opening/closing modals, and navigating features accumulates orphaned listeners
This causes memory leaks and potential duplicate-handler bugs (e.g., handlers firing multiple times after re-initialization)

Recommendation

Use AbortController pattern: pass a single signal to all addEventListener calls, then controller.abort() to clean up all at once
Track listeners per module and clean up on teardown
Add cleanup/destroy methods to each module that removes its listeners

## Finding Frontend JS has **2,225 addEventListener** calls but only **242 removeEventListener** calls — a 9:1 ratio indicating systematic listener leaks. Worst offenders: | File | addEventListener | removeEventListener | |------|-----------------|-------------------| | document.js | 211 | 21 | | chat.js | 30 | **0** | | notes.js | 144 | 8 | | settings.js | 157 | 3 | | emailLibrary.js | 111 | 13 | | slashCommands.js | 57 | 54 | ## Impact - **chat.js** has zero cleanup — every listener added is permanent - **notes.js** leaks 136 listeners (144 added, 8 removed) - **settings.js** leaks 154 listeners - Over time, switching sessions, opening/closing modals, and navigating features accumulates orphaned listeners - This causes memory leaks and potential duplicate-handler bugs (e.g., handlers firing multiple times after re-initialization) ## Recommendation 1. Use AbortController pattern: pass a single `signal` to all addEventListener calls, then `controller.abort()` to clean up all at once 2. Track listeners per module and clean up on teardown 3. Add cleanup/destroy methods to each module that removes its listeners