create tic tac toe game

function player(name, symbol) {
  return {
    name: name,
    symbol: symbol,
    score: 0,
  }
}
    
function game(player1, player2) {
  return {
    cells: Array(9).fill(null),
    player1: player1,
    player2: player2,
    currentTurn: player1,
  }
}

function play(game, cellIndex) {
  const newCells = game.cells.slice()
  newCells[cellIndex] = game.currentTurn.symbol
  const newGame = Object.assign({}, game, { cells: newCells })
  if (newGame.currentTurn === newGame.player1) {
    newGame.currentTurn = newGame.player2
  } else {
    newGame.currentTurn = newGame.player1
  }
  return newGame
}

function checkForWinner(game) {
  const winningCombos = [
    [0, 1, 2],
    [3, 4, 5],