Find Winner on a Tic Tac Toe Game LeetCode solution in JavaScript

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/**
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 * @param {number[][]} moves
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 * @return {string}
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 */
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let validate = (arr) => {
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  let set = [...new Set(arr)];
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  return set.length == 1 && set[0] != 0;
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};
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var tictactoe = function (moves) {
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  let grid = [
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    [0, 0, 0],
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    [0, 0, 0],
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    [0, 0, 0],
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  ];
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  for (let i in moves) {
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    let [x, y] = moves[i];
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    grid[x][y] = i % 2 == 1 ? -1 : 1;
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    if (
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      validate(grid[x]) ||
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      validate(grid.reduce((prev, curr) => [...prev, curr[y]], [])) ||
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      validate([grid[0][0], grid[1][1], grid[2][2]]) ||
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      validate([grid[0][2], grid[1][1], grid[2][0]])
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    )
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      return i % 2 ? "B" : "A";
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  }
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  return moves.length == 9 ? "Draw" : "Pending";
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};