You are given a 3 × 3 Tic-tac-toe board stored as a two-dimensional array. Find out the winner of the game, or return ' ' if there is no winner.

TicTacToe.js

TicTacToe = (board) => {
  let winbits = [7,56,73,84,146,273,292,448];
  board = Array.prototype.concat.apply([], board);

  query = player => {
    num = 0;
    board.forEach((cell, i) => {
      var i = (board.length-i)-1;
      num += (cell === player)<<i;
    });
    return num;
  };

  test = player => {
    result = query(player);
    return !winbits.every(winbit => {
      return !((result&winbit) === winbit);
    });
  };

  if (test('x')) {
    return 'x';
  } else if (test('o')) {
    return 'o';
  } else {
    return ' ';
  }
}

// The boards
let boardOne = [['x', 'x', 'x'],
                [' ', 'o', ' '],
                ['o', ' ', 'x']];

let boardTwo = [['x', 'x', 'o'],
                [' ', 'o', ' '],
                ['o', ' ', 'x']];

let boardThree = [['x', ' ', ' '],
                  [' ', 'x', ' '],
                  [' ', ' ', 'o']];

let winnerOne = TicTacToe(boardOne); // winnerOne === 'x'
let winnerTwo = TicTacToe(boardTwo); // winnerTwo === 'o'
let winnerThree = TicTacToe(boardThree); // winnerThree === ' '