Episode 07 game · Chitragupta · Water
Drain the Kappa’s Pond
Kai’s app gets slower with every click. Use it and watch what piles up on window, give each leaky effect the right cleanup, then prove it with ten visits.
window'resize' listeners1
1 · Feel the leak
Use Kai’s app like a real visitor: switch between Search, Home and Profile at least eight times. Watch what stays behind on window after each page closes.
2 · Give each effect its cleanup
Each page starts something in a useEffect and never stops it. Pick the cleanup that really stops it.
3 · The ten-visit test
A fresh tab, your fixed effects, and ten fast visits. If the ledger holds at one of each, the pond drains.
New seal earned
Pond drained
Acharya’s Rule #7Whatever you subscribe to, you must unsubscribe from.
React removes the page’s DOM, not the listeners and timers your effect added.
Undo what the effect started: remove, clear, close or abort.
removeEventListener only removes the exact function you added.