Time: 0:00
Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).
This bug belongs to the off-by-one errors pattern
The loop that runs one time too many, the slice that drops the last item, the index that starts in the wrong place.
What went wrong: the last n items start at index arr.length - n. The extra - 1 starts one item earlier, so you get one item too many.
The fix: return arr.slice(arr.length - n);
Remember: check index maths with a small example on paper.
The pattern behind it: off-by-one errors.
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<iframe src="https://trybughunt.com/embed/5c1879cc-a725-4f82-8f7f-083b406a3a26" title="Debugging challenge: Last 2 items comes back with 3" width="100%" height="580" loading="lazy" style="border:1px solid #d4d4d8;border-radius:12px;max-width:760px"></iframe>
<p style="font-size:14px">Debugging challenge from <a href="https://trybughunt.com/challenges/5c1879cc-a725-4f82-8f7f-083b406a3a26">TryBugHunt</a></p>