Function purpose is to create a NxN spiral with a given size

make-spiral.js

/**
output of size = 5 example:

00000
....0
000.0
0...0
00000
**/

var spiralize = function(size) {
  function createGrid(size) {
    let grid = [];
    grid[0] = Array(size).fill(1);
    for(let a=1;a<size;a++){
      grid[a] = Array(size).fill(0);
    }
    return grid;
  }
    
  function spiral(grid,direction,counter,gap, distance) {
    let shouldDeduct = !(direction%2);
    let prevGrid = [...grid];
    let startFrom = distance-gap;

    switch(direction) {
      case 0:
          for(let a=startFrom;a<distance;a++) {
              grid[grid.length-distance][a] = 1;
          }
          break;
      case 1:
          for(let a=startFrom;a<distance;a++) {
              grid[a][distance-1] = 1;
          }
          break;
      case 2:
          for(let a=startFrom;a<distance;a++) {
              grid[distance-1][a] = 1;
          }
          break;
      case 3:
          for(let a=startFrom;a<distance;a++) {
              grid[a][grid.length-distance] = 1;
          }
        break;
    }
    if(direction >= 3) {
        distance = distance-2;
        direction = 0;
    } else {
        direction++;
    }
    counter++;
    if(shouldDeduct) {
        gap = gap-2;
    }
    if(counter < size-1){
        return spiral(grid,direction,counter,gap,distance);
    }
    return prevGrid;
  }

  let grid = createGrid(size);
  let result = spiral(grid,1,0,grid.length, grid.length);

  return result;
}