Maze algorithm

Building a maze

1. create a grid of cells
2. pick a random starting cell
3. for that cell, build a random-ordered list of neighbors
4. if a neighbor has been visited before, remove it from the list
5. for each remaining neighbor, move to it and remove the wall between those two cells
6. repeat '2' for this new neighbor

const grid = Array(cells)
  .fill(null)
  .map(() => Array(cells).fill(false));
const verticals = Array(cells)
  .fill(null)
  .map(() => Array(cells - 1).fill(false));
const horizontals = Array(cells - 1)
  .fill(null)
  .map(() => Array(cells).fill(false));

const startRow = Math.floor(Math.random() * cells);
const startCol = Math.floor(Math.random() * cells);
console.log(startRow, startCol);

const stepThroughCell = (row, column) => {
  // If i have visted the cell at [row, column], then return
  if (grid[row][column]) {
    return;
  }

  // Mark this cell as being visited
  grid[row][column] = true;

  // Assemble randomly-ordered list of neighbors
  const neighbors = shuffle([
    [row - 1, column, "up"],
    [row, column + 1, "right"],
    [row + 1, column, "down"],
    [row, column - 1, "left"],
  ]);
  // For each neighbor....
  for (let neighbor of neighbors) {
    const [nextRow, nextColumn, direction] = neighbor;

    // See if that neighbor is out of bounds
    if (
      nextRow < 0 ||
      nextRow >= cells ||
      nextColumn < 0 ||
      nextColumn >= cells
    ) {
      continue;
    }

    // If we have visited that neighbor, continue to next neighbor
    if (grid[nextRow][nextColumn]) {
      continue;
    }

    // Remove a wall from either horizontals or verticals
    if (direction === "left") {
      verticals[row][column - 1] = true;
    } else if (direction === "right") {
      verticals[row][column] = true;
    } else if (direction === "up") {
      horizontals[row - 1][column] = true;
    } else if (direction === "down") {
      horizontals[row][column] = true;
    }

    stepThroughCell(nextRow, nextColumn);
  }
};