How would you answer an interview scenario involving useEffect and side effects in React?

For an interview scenario involving useEffect and side effects, I would first clarify the business goal, scale, constraints, and the failure or quality attribute the interviewer wants to explore. useEffect runs side-effect logic after rendering, such as subscriptions, timers, imperative browser APIs, or synchronization with an external system. In this scenario, if a component subscribes to a WebSocket channel, create the subscription in an effect and return a cleanup function that unsubscribes when the channel or component changes. For production, use effects only when synchronizing with something external. Declare all reactive dependencies, return cleanup where necessary, and split unrelated effects into separate hooks. I would then explain the main alternatives and tradeoffs, identify likely failure modes, and describe how I would validate the solution through testing, observability, security controls, and recovery or rollback planning.