getpath.js

function getPath(startX, startY, endX, endY) {
  // Initialize an empty array to store the coordinates of the points on the path
  let path = [];

  // Use the Bresenham's line algorithm to get the coordinates of the points on the path
  let x1 = startX, y1 = startY, x2 = endX, y2 = endY;
  let isSteep = Math.abs(y2 - y1) > Math.abs(x2 - x1);
  if (isSteep) {
    [x1, y1] = [y1, x1];
    [x2, y2] = [y2, x2];
  }
  let isReversed = false;
  if (x1 > x2) {
    [x1, x2] = [x2, x1];
    [y1, y2] = [y2, y1];
    isReversed = true;
  }
  let deltax = x2 - x1, deltay = Math.abs(y2 - y1);
  let error = Math.floor(deltax / 2);
  let y = y1;
  let ystep = null;
  if (y1 < y2) {
    ystep = 1;
  } else {
    ystep = -1;
  }
  for (let x = x1; x <= x2; x++) {
    if (isSteep) {
      path.push([y, x]);
    } else {
      path.push([x, y]);
    }
    error -= deltay;
    if (error < 0) {
      y += ystep;
      error += deltax;
    }
  }

  // If the line is reversed, reverse the order of the points in the path
  if (isReversed) {
    path = path.reverse();
  }

  return path;
}