monkeytypegame / monkeytypegame/monkeytype

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

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TypeScript
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Description

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Does the issue happen when logged in?

Yes

Does the issue happen when logged out?

Yes

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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:

// 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.:

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

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start in frontend/src/ts/states/test.ts, where outOfFocusTimeouts is populated, and inspect utils/misc.ts:148-153, where clearTimeouts handles the entries. Trace the callers to confirm whether clearing all stored IDs or retaining only the latest ID preserves the intended blur/refocus behavior. Done means cleared timeout IDs are no longer retained and repeated unfocus/refocus events no longer grow the array indefinitely.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
frontend, performance
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Active
Clarity
Clearly specified
Newbie friendliness
84/100

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