Implement uniqueBy(arr, keyFn)

Created byeLearn Core Team

Implement `uniqueBy(arr, keyFn)`

Write uniqueBy(arr, keyFn) that removes duplicates based on keyFn(item), keeping the first occurrence of each key and preserving order.

uniqueBy(
  [{ id: 1 }, { id: 2 }, { id: 1 }],
  (x) => x.id
); // [{ id: 1 }, { id: 2 }]

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