Code reviewMediumcr-g394

Subject Effect dependenciesLevel Mid–Senior~18 minCommon in Code quality & review interviewsIndustries Software development

Question

Review this React TypeScript subscription component.

What a strong answer looks like

Separate real bugs from style. Rank issues by severity, point at the root cause rather than the symptom, and suggest a concrete fix — specific and kind.

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Code to reviewtsx

1function RoomPresence({ roomId, onCount }: { roomId: string; onCount: (n: number) => void }) {2  useEffect(() => {3    const sub = subscribe(roomId, (members) => {4      onCount(members.length);5    });6    return () => sub.unsubscribe();7  }, [roomId]);8 9  return null;10}

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