Script to check for valid boggle game guesses

gistfile1.txt

const checkWord = (board, word) => {
  const boardMap = boardToMap(board);
  const startPoints = Array.from(boardMap.values());
  if (!startPoints) {
    return false;
  }

  return checkNodes(boardMap, startPoints, [], [], word.split(''), 0);
};

const boardToMap = board => {
  const boardMap = new Map();
  for (let y = 0; y < board.length; y++) {
    for (let x = 0; x < board[y].length; x++) {
      const coord = { y, x };
      boardMap.set(JSON.stringify(coord), {
        coord,
        letter: board[y][x],
        children: getAdjacentNodes(board, coord)
      });
    }
  }

  return boardMap;
};

const getAdjacentNodes = (board, srcCoord) => {
  const checks = [[-1, -1], [-1, 0], [-1, 1],
    [0, -1], [0, 1], [1, -1], [1, 0], [1, 1]
  ];
  const adjacentNodes = [];
  checks.forEach(adjCoord => {
    const coord = {
      y: srcCoord.y + adjCoord[0],
      x: srcCoord.x + adjCoord[1]
    };
    if (board[coord.y] && board[coord.x]) {
      adjacentNodes.push(JSON.stringify(coord));
    }
  });
  return adjacentNodes;
};

const checkNodes = (boardMap, nodes, checked = [], checkedNodes = [], wordArr, index) => {
  if (checked.join('') === wordArr.join('')) {
    return true;
  }

  const validNodes = nodes.filter(node => node.letter === wordArr[index]);

  return !validNodes ? false : validNodes.some(node => {
    const currentKey = JSON.stringify(node.coord);
    return checkedNodes.indexOf(currentKey) === -1 &&
      checkNodes(boardMap, node.children.map(key => boardMap.get(key)),
        checked.concat(wordArr[index]), checkedNodes.concat(currentKey), wordArr, index + 1);
  });
};