Game of life experiment

game-of-life.js

/**
Quick POC for game of life. Terrible side effects. Actually doing this in Rust but wanted to quickly knock something out in js
**/
let width = 40

function getCells() {
  return new Array(width * width).fill(false)
}

let cells = getCells()

cells[1] = true
cells[2] = true
cells[6] = true
cells[30] = true
cells[31] = true
cells[26] = true
cells[51] = true
cells[52] = true
cells[53] = true
cells[54] = true
cells[125] = true
cells[126] = true
cells[145] = true
cells[146] = true
cells[167] = true
cells[168] = true
cells[187] = true
cells[188] = true
cells[221] = true
cells[222] = true
cells[223] = true
cells[382] = true
cells[403] = true
cells[421] = true
cells[422] = true
cells[423] = true

// Any live cell with fewer than two live neighbours dies, as if by underpopulation
// Any live cell with two or three live neighbours lives on to the next generation
// Any live cell with more than three live neighbours dies, as if by overpopulation
// Any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction
function getCell(cell, neighbours) {
  if (cell) {
    if (neighbours === 2 || neighbours === 3) {
      return true
    }
    return false
  } else {
    if (neighbours === 3) {
      return true
    }
    return false
  }
}

function regenerate() {
  let newCells = []
  for (let i = 0, w = 0; i < width * width; i++, w++) {
    if (!(i % width)) {
      w = 0
    }

    let neighbours = [cells[i - (width - 1)],
      cells[i - width], cells[i - (width + 1)],
      cells[i - 1], cells[i + 1],
      cells[i + (width - 1)], cells[i + width], cells[i + (width + 1)]
    ].reduce((curr, next) => next ? curr + 1 : curr, 0)

    newCells.push(getCell(cells[i], neighbours))
    w++
  }
  cells = newCells
}

function drawGrid() {
  let grid = ''
  for (let i = 0, w = 0; i < width * width; i++) {
    if (!(i % width)) {
      w = 0
      grid += '\n'
    }
    grid += `| ${cells[i] ? 'x' : ' '} |`
  }
  console.log(grid)
}

setInterval(() => {
  drawGrid()
  regenerate()
}, 500)