#8366·monkeytype

Bug: outOfFocusTimeouts array grows unboundedly — cleared timeout ids never removed from array

Author: priyanshu1976Created Aug 26, 2026Updated Aug 26, 2026

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Does the issue happen when logged in?

Yes

Does the issue happen when logged out?

Yes

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Yes

Does the issue happen in incognito mode when logged out?

Yes

Issue details

Current Behavior

outOfFocusTimeouts in frontend/src/ts/states/test.ts accumulates timeout ids forever:

typescript
// states/test.ts:38-54
const outOfFocusTimeouts: (number | NodeJS.Timeout)[] = [];
...
} else {
  outOfFocusTimeouts.push(
    setTimeout(() => { set(val); }, 1000),
  );
}

Every unfocus event pushes a new id onto the array. clearTimeouts() (utils/misc.ts:148-153) only calls clearTimeout on each entry but never removes them from the array, so the array grows monotonically for the entire session. Long sessions with frequent alt-tabbing accumulate thousands of stale numeric ids (small but unnecessary retained memory, and the array scan in clearTimeouts grows linearly).

Expected Behavior

Remove consumed entries after clearing, e.g.:

typescript
export function clearTimeouts(timeouts: (number | NodeJS.Timeout)[]): void {
  timeouts.forEach((to) => clearTimeout(to));
  timeouts.length = 0;
}

or store only the latest timeout id, since scheduling a newer unfocus supersedes older pending ones anyway.

Steps To Reproduce

  1. Open devtools memory snapshot / add a breakpoint log on outOfFocusTimeouts.push.
  2. Blur/refocus the window repeatedly during tests.
  3. Array length increases without bound and is never reset.

Environment

  • OS: Any
  • Browser: Any
  • Found via source review of master @ 91bd24bb8

Source: monkeytypegame/monkeytype