Simple 2D Maze Generator

maze.js

// Maze Generator
// (c) 2017, Bang Bang Attack Studios
// http://www.bangbangattackstudios.com

const random = options => {
  const index = Math.random() * options.length
  return options[~~index]
}

const maze = (width, height, factory) => {
  const stack = [
    [1, 1, width - 2, height - 2]
  ]

  const map = []

  for (let column = 0; column < width; column += 1) {
    map.push([])
    for (let row = 0; row < height; row += 1) {
      const edge = (column === 0 || row === 0 || column + 1 === width || row + 1 === height)
      map[column].push(edge ? 1 : 0)
    }
  }

  const partitionRoom = room => {
    const ax = []
    const ay = []

    for (let i = room[0] + 1; i < room[2]; i += 1) {
      const top = map[i][room[1] - 1]
      const bottom = map[i][room[3] + 1]

      if (i % 2 === 0 && top && bottom) {
        ax.push(i)
      }
    }

    for (let i = room[1] + 1; i < room[3]; i += 1) {
      const left = map[room[0] - 1][i]
      const right = map[room[2] + 1][i]

      if (i % 2 === 0 && left && right) {
        ay.push(i)
      }
    }

    if (!ax.length || !ay.length) {
      return
    }

    const x = random(ax)
    const y = random(ay)

    map[x][y] = 1

    const walls = []
    const left = []
    const right = []
    const top = []
    const bottom = []

    walls.push(left)
    walls.push(right)
    walls.push(top)
    walls.push(bottom)

    for (let i = room[0]; i < x; i += 1) {
      map[i][y] = 1
      left.push([i, y])
    }

    for (let i = x + 1; i <= room[2]; i += 1) {
      map[i][y] = 1
      right.push([i, y])
    }

    for (let i = room[1]; i < y; i += 1) {
      map[x][i] = 1
      top.push([x, i])
    }

    for (let i = y + 1; i <= room[3]; i += 1) {
      map[x][i] = 1
      bottom.push([x, i])
    }

    const solid = random(walls)

    walls.forEach(wall => {
      if (wall !== solid) {
        const hole = random(wall)
        map[hole[0]][hole[1]] = 0
      }
    })

    stack.push([room[0], room[1], x - 1, y - 1])
    stack.push([x + 1, room[1], room[2], y - 1])
    stack.push([room[0], y + 1, x - 1, room[3]])
    stack.push([x + 1, y + 1, room[2], room[3]])
  }

  while (stack.length) {
    partitionRoom(stack.shift())
  }

  for (let column = 0; column < width; column += 1) {
    for (let row = 0; row < height; row += 1) {
      factory && factory(column, row, map[column][row])
    }
  }

  return map
}

module.exports = maze