Advent of Code 2023 - Day 21 - Parser

const key = (i, j) => {
  return `${i},${j}`;
};
const parse = (input) => {
  const grid = utils.getInputLines(input).map((e) => e.trim().split(""));
  const walls = {};
  const plots = {};
  let start = { i: 0, j: 0 };
  for (let i = 0; i < grid.length; i++) {
    for (let j = 0; j < grid[i].length; j++) {
      const value = grid[i][j];
      if (value == "#") {
        walls[key(i, j)] = true;
      }
      if (value == "S") {
        plots[key(i, j)] = -1;
        start = { i: i, j: j };
      }
    }
  }
  return {
    walls: walls,
    plots: plots,
    start: start,
    size: grid.length,
  };
};