gameOfLife.js

/* GAME OF LIFE
  1. Any live cell with fewer than two live neighbours dies.
  2. Any live cell with two or three live neighbours lives on to the next generation.
  3. Any live cell with more than three live neighbours dies.
  4. Any dead cell with exactly three live neighbours becomes a live cell.
*/

const blinkerSeed = {
  height: 5,
  coords: [[2,1], [2,2], [2,3]]
};

function buildGameBoard(height){
  const gameBoard = [];
  //build board
  for (let i = 0; i < height; i++){
    gameBoard.push((new Array(height)).fill(0));
  }
  return gameBoard;
}

let currentBoard = buildGameBoard(blinkerSeed.height);

// fill board
for (let i = 0; i < blinkerSeed.coords.length; i++){
  const cell = blinkerSeed.coords[i];
  currentBoard[cell[1]][cell[0]] = 1;
}
//console.log(currentBoard);

const update = () => {
  const newBoard = buildGameBoard(blinkerSeed.height);
  const gameBoard = currentBoard;
  //console.log(newBoard)
  const setBoard = (row, col, val) => {
    //console.log(`${row},${col}`,newBoard);
   // console.log(`${row},${col}`, newBoard[row,col])
    newBoard[row][col] = val;
  };

  for (let i = 0; i < gameBoard.length; i++){
    for (let j = 0; j < gameBoard[i].length; j++){
      let neighbors = 0;
      // get neighborcount
      
      // top row
      if ((gameBoard[i - 1]||[])[j - 1]) neighbors++;
      if ((gameBoard[i - 1]||[])[j    ]) neighbors++;
      if ((gameBoard[i - 1]||[])[j + 1]) neighbors++;

      // middle row
      if ((gameBoard[i    ]||[])[j - 1]) neighbors++;
      if ((gameBoard[i    ]||[])[j + 1]) neighbors++;
      
      // bottom row
      if ((gameBoard[i + 1]||[])[j - 1]) neighbors++;
      if ((gameBoard[i + 1]||[])[j    ]) neighbors++;
      if ((gameBoard[i + 1]||[])[j + 1]) neighbors++;
      
      const cell = gameBoard[i][j]; //console.log(neighbors)
      if (cell && neighbors < 2) setBoard(i,j,0);
      else if (cell && (neighbors == 2 || neighbors == 3)) setBoard(i,j,1);
      else if (cell && neighbors > 3) setBoard(i,j,0);
      else if (!cell && neighbors == 3) setBoard(i,j,1);
      else setBoard(i,j,0);
    }
  }
  console.log(newBoard);
  currentBoard = newBoard;
};

setInterval(()=>{
  update()
}, 1000)