Game of Life in javascript

gameoflife.js

const SIZE = 24;

const generateBoard = () => {
  return Array.from({ length: SIZE }, () => {
    // return a row
    return Array.from({ length: SIZE }, () => Math.round(Math.random()));
  });
};

const printBoard = board => {
  console.clear();
  const lines = board
    .map(row =>
      row
        .join("")
        .replace(/0/g, "🌑 ")
        .replace(/1/g, "🦠 ")
    )
    .join("\n");
  console.log(lines);
};

const getCell = (rowIndex, cellIndex, board) => {
  if (!board[rowIndex]) return 0;
  if (!board[rowIndex][cellIndex]) return 0;
  return board[rowIndex][cellIndex];
};

const sleep = ms => new Promise(resolve => setTimeout(resolve, ms));

let rounds = 0;

const play = async board => {
  rounds += 1;
  printBoard(board);

  const nextBoard = board.map((row, rowIndex) => {
    return row.map((cell, cellIndex) => {
      const neighbors = [
        // up
        getCell(rowIndex - 1, cellIndex, board),
        //top left
        getCell(rowIndex - 1, cellIndex - 1, board),
        // left
        getCell(rowIndex, cellIndex - 1, board),
        //bottom left
        getCell(rowIndex + 1, cellIndex - 1, board),
        // bottom
        getCell(rowIndex + 1, cellIndex, board),
        //bottom right
        getCell(rowIndex + 1, cellIndex + 1, board),
        // right
        getCell(rowIndex, cellIndex + 1, board),
        //top right
        getCell(rowIndex - 1, cellIndex + 1, board)
      ];

      const count = neighbors.reduce((acc, n) => acc + n, 0);
      if (count === 0) {
        return 0;
      } else if (count === 1) {
        return 0;
      } else if (count === 2) {
        return cell;
      } else if (count === 3) {
        return 1;
      } else {
        return 0;
      }
    });
  });

  // END on:
  // all the same as the last time
  // all 0s
  if (JSON.stringify(board) === JSON.stringify(nextBoard)) {
    console.log("");
    console.log("done!");
    console.log(rounds + " rounds");
  } else {
    await sleep(300);
    play(nextBoard);
  }
};

const initialBoard = generateBoard();
play(initialBoard);