Code Review (Easy): Tracing Project Tags

Story

Lena is refining a search utility for the ReviewThat Labs internal dashboard that helps users locate specific keywords within a grid of project tiles. The tool works by checking if a target word can be formed by connecting neighboring tiles horizontally or vertically, ensuring that no single tile is reused in the path. Eva Harrington reviewed the draft and noted that if a grid features the letters 'S', 'E', and 'E' in adjacent positions, the search for 'SEE' should return a positive match. This feature will make it much easier for the team to navigate dense clusters of information across the platform.

Your Task

Read the story and code, then decide if the code is ready for production or needs improvement.

Hints

What would block an approval? Give me a hint.

function exist(board: string[][], word: string, performPrecheck = true, useReverseHeuristic = true): boolean {
  const m = board.length;
  if (m === 0) return false;
  const n = board[0].length;
  if (word.length === 0) return true;

let boardCount: Map<string, number> | null = null;

// Optionally perform count-based feasibility check
  if (performPrecheck) {
    boardCount = new Map<string, number>();
    for (let i = 0; i < m; i++) {
      for (let j = 0; j < n; j++) {
        const ch = board[i][j];
        boardCount.set(ch, (boardCount.get(ch) ?? 0) + 1);
      }
    }

// Heuristic: possibly reverse word based on letter rarities
  if (useReverseHeuristic && boardCount) {
    const firstChar = word[0];
    const lastChar = word[word.length - 1];
    if ((boardCount.get(firstChar) ?? 0) > (boardCount.get(lastChar) ?? 0)) {
      word = word.split('').reverse().join('');
    }
  }

const dirs = [
    [0, 1],
    [0, -1],
    [1, 0],
    [-1, 0],
  ];

// Universal function that either starts the search from a cell or performs the DFS based on the flag.
  function proc(i: number, j: number, k: number, doDfs: boolean): boolean {
    if (!doDfs) {
      if (i < 0 || i >= m || j < 0 || j >= n) return false;
      if (board[i][j] !== word[0]) return false;
      return proc(i, j, 0, true);
    }

// DFS branch
    if (k === word.length) return true;
    if (i < 0 || i >= m || j < 0 || j >= n) return false;
    if (board[i][j] !== word[k]) return false;

if (k === word.length - 1) return true;

const saved = board[i][j];
    board[i][j] = '#';

for (const [di, dj] of dirs) {
      const ni = i + di;
      const nj = j + dj;
      if (proc(ni, nj, k + 1, true)) {
        board[i][j] = saved;
        return true;
      }
    }

board[i][j] = saved;
    return false;
  }

for (let i = 0; i < m; i++) {
    for (let j = 0; j < n; j++) {
      if (proc(i, j, 0, false)) return true;
    }
  }

return false;
}