gameOfLife.js

'use strict';
var lifeBoard = (function() {
  var publicAPI,
  xsize = 20,
  ysize = 20,
  Board = [],
  dead = 0,
  alive = 1,
  boardSetupSelect = document.getElementById("boardSetup"),
  BoardSetup = boardSetupSelect.value;

              function _neighbors(Board, x, y) {
                var n = 0;
                for (var dx = -1; dx <= 1; dx += 1) {
                  for (var dy = -1; dy <= 1; dy += 1) {
                    if ((dx === 0) &&  (dy === 0)) {
                      continue;
                    }
                    var ax = x + dx;
                    var ay = y + dy;
                    if ((ax < 0 || ay < 0) || (ax > (xsize)) || (ay > (ysize))) {
                      continue;
                    } else if (Board[ax][ay] === alive) {
                      n += 1;
                    } 
                  }
                }
                return n;
              }

              function _kill(newBoard, x,y) {
                if (newBoard[x][y] === alive) {
                  newBoard[x][y] = dead;
                }    
              }

              function _makeLive(newBoard, x,y) {
                if (newBoard[x][y] === dead) {
                  newBoard[x][y] = alive;
                }
              }

              function _nextStep(newBoard) {
                var cell, n;
                for (var x = 0; x <= xsize; x += 1) {
                  for (var y = 0; y <= ysize; y += 1) {
                    cell = Board[x][y];
                    n = _neighbors(Board, x,y);
                    if ( n === 3) {
                      _makeLive(newBoard, x,y);
                    } else if ((cell === alive) && (n === 2)) {
                      _makeLive(newBoard, x,y);
                    } else {
                      _kill(newBoard, x, y); 
                    }
                  }
                }
              }

              function _drawBoard(newBoard) {
                var boardTable = document.getElementById("boardTable");
                var tr, td, i;
                boardTable.innerHTML = "";
                for (var y = 0; y <= ysize; y += 1) {
                  //populate table row
                  tr = document.createElement("tr");
                  tr.setAttribute("id", "tableRow" + y);
                  boardTable.appendChild(tr);
                  for (var x = 0; x <= xsize; x += 1) {
                    //populate table data cells
                    td = document.createElement("td");

                    tr.appendChild(td);
                    i = document.createElement("div");
                    if (newBoard[x][y] === alive) {
                      i.setAttribute("class", "alive");
                    } else {
                      i.setAttribute("class", "dead");

                    }

                    td.appendChild(i);

                  }
                }
                Board = newBoard.slice(0);
              }

              function main() {
                // *** Change this variable to choose a different board setup from below
                //var url = window.location.pathname;
                //var filename = url.substring(url.lastIndexOf('/')+1);
                //filename = filename.substring(0, filename.indexOf('.'));  
                Board[xsize] = 0;
                for (var x = 0; x <= xsize; x += 1) {

                  Board[x] = [0];
                  for (var y = 0; y <= ysize; y += 1) {
                    Board[x][y] = 0;
                  }
                }

                if (BoardSetup === "blinker") {
                  Board[1][0] = 1;
                  Board[1][1] = 1;
                  Board[1][2] = 1;
                } else if (BoardSetup === "glider") {
                  Board[2][0] = 1;
                  Board[2][1] = 1;
                  Board[2][2] = 1;
                  Board[1][2] = 1;
                  Board[0][1] = 1;
                } else if (BoardSetup === "flower") {
                  Board[4][6] = 1;
                  Board[5][6] = 1;
                  Board[6][6] = 1;
                  Board[7][6] = 1;
                  Board[8][6] = 1;
                  Board[9][6] = 1;
                  Board[10][6] = 1;
                  Board[4][7] = 1;
                  Board[6][7] = 1;
                  Board[8][7] = 1;
                  Board[10][7] = 1;
                  Board[4][8] = 1;
                  Board[5][8] = 1;
                  Board[6][8] = 1;
                  Board[7][8] = 1;
                  Board[8][8] = 1;
                  Board[9][8] = 1;
                  Board[10][8] = 1;
                }

                _drawBoard(Board);
                document.getElementById("nextButton").addEventListener("click", _nextHandler);
                boardSetupSelect.addEventListener("change", _selectHandler);
              }

              function _nextHandler() {
                var newBoard = [];
                for (var x = 0; x <= xsize; x += 1) {

                  newBoard[x] = [];
                  for (var y = 0; y <= ysize; y += 1) {
                    newBoard[x][y] = Board[x][y];
                  }
                }
                _nextStep(newBoard); 
                _drawBoard(newBoard);
              }

              function _selectHandler(event) {
                BoardSetup = event.target.value;
                main();
              }

              publicAPI = {
                main: main
              };
              return publicAPI;
})();

window.onload = lifeBoard.main;