Fix the replay of a frozen counter hook
Your task
Your team's live counter froze at 1. Its React hook calls setCount(count + 1) from a setInterval, set up once by an effect with an empty dependency list. The callback keeps the count from the first render. For the postmortem, the team wants a replay that shows the number on screen after each event.
An assistant wrote simulate_counter(events, use_functional). It is in the editor. It has a bug. Find it and fix it.
Input and output:
events: event names, in order.use_functional: true when the hook uses the updater formsetCount(c => c + 1), false when it usessetCount(count + 1).- Return the numbers on screen, one after each event that counts, in order.
Rules the tests check:
- The count starts at 0. The value the interval callback captured also starts at 0.
"tick": the interval fires once. With the updater form, the count becomes the current count plus 1. Otherwise it becomes the captured value plus 1. Record the count."remount": the effect is torn down and set up again. The new callback captures the current count. The count itself does not change. Record it.- Any other event, such as
"pause", changes nothing and records nothing. Names are case sensitive. - No events returns an empty list.
Examples
simulate_counter(events: list[str], use_functional: bool) -> list[int]Example 1
Input
simulate_counter(["tick", "tick", "tick"], False)Output
[1, 1, 1]Example 2
Input
simulate_counter(["tick", "tick", "tick"], True)Output
[1, 2, 3]Example 3
Input
simulate_counter(["tick", "tick", "remount", "tick", "tick"], False)Output
[1, 1, 1, 2, 2]