Imperative Game of Life

imperative-conways-game-of-life.js

function conwaysGameOfLife(board) {
  var newBoard = []
  for (var i = 0; i < board.length; i++) {
    newBoard.push([])
    for (var j = 0; j < board[i].length; j++) {
      newBoard[i].push(0)
    }
  }

  for (var i = 0; i < board.length; i++) {
    for (var j = 0; j < board[i].length; j++) {
      var neighbors = 0
      if (i > 0 && j > 0 && board[i - 1][j - 1] === 1) {
        neighbors++
      }
      if (i > 0 && board[i - 1][j] === 1) {
        neighbors++
      }
      if (i > 0 && j < board[i].length - 1 && board[i - 1][j + 1] === 1) {
        neighbors++
      }
      if (j > 0 && board[i][j - 1] === 1) {
        neighbors++
      }
      if (j < board[i].length - 1 && board[i][j + 1] === 1) {
        neighbors++
      }
      if (i < board.length - 1 && j > 0 && board[i + 1][j - 1] === 1) {
        neighbors++
      }
      if (i < board.length - 1 && board[i + 1][j] === 1) {
        neighbors++
      }
      if (
        i < board.length - 1 &&
        j < board[i].length - 1 &&
        board[i + 1][j + 1] === 1
      ) {
        neighbors++
      }

      // if the cell is alive
      if (board[i][j] === 1) {
        // if the cell has 2 or 3 neighbors, it lives
        if (neighbors === 2 || neighbors === 3) {
          newBoard[i][j] = 1
        }
      } else {
        // if the cell is dead
        // if the cell has 3 neighbors, it comes alive
        if (neighbors === 3) {
          newBoard[i][j] = 1
        }
      }
    }
  }

  return newBoard
}

var board = Array.from({ length: 50 }, () =>
  Array.from({ length: 50 }, () => Math.round(Math.random()))
)

;(async () => {
  let x = 1000
  for (let i = 0; i < x; i++) {
    console.clear()
    board = conwaysGameOfLife(board)
    console.log(board.map((i) => i.join(" ")).join("\n"))
    await new Promise((resolve) => setTimeout(resolve, 250))
  }
})()