Review Summary

I am approving your solution because it correctly implements Array.prototype.sort2 according to the task requirements and behaves as expected for the tested inputs. You add sort2 via [].__proto__.sort2 without touching Array.prototype.sort, which aligns with the constraint not to override or call the built-in sort. The sorting is performed in place using a manual nested-loop swap, and the function returns this, so the original array reference is preserved as required. When no compareFunction is provided, you compare String(element1) and String(element2) to achieve the MDN-like lexicographic behavior; for example, numeric arrays like [3, 12, 2, 11].sort2() produce [11, 12, 2, 3], which matches the expected output. When a custom compareFunction is supplied, you correctly use the sign of its return value (> 0, < 0, === 0) to determine ordering, ensuring compatibility with standard sort-style comparators. Overall, there are no critical or blocking issues, and your code is clear and fulfills all functional and checklist requirements. Nice work meeting the constraints and mirroring the behavior of the native sort in a custom implementation.

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