shellquest/src/utils/terminalSize.ts

Terminal-based procedurally generated dungeon crawler

export function watchTerminalSize(cb: (w: number, h: number) => void, pollMs = 200) {
  let w = process.stdout.columns || 80;
  let h = process.stdout.rows || 24;

  const fire = () => cb(w, h);

  // Bun ≤ 1.2 on Windows: force-refresh before every read
  const refreshIfNeeded = () => {
    if (process.versions.bun && process.platform === 'win32') {
      // ⚠️ private API, may change without notice
      (process.stdout as any)._refreshSize?.();
    }
  };

  const poll = () => {
    refreshIfNeeded();
    const nw = process.stdout.columns || 80;
    const nh = process.stdout.rows || 24;
    if (nw !== w || nh !== h) {
      w = nw;
      h = nh;
      fire();
    }
  };

  // 1️⃣ TTY “resize” (Node & future Bun)
  if (process.stdout.isTTY) {
    process.stdout.on?.('resize', () => {
      refreshIfNeeded();
      poll();
    });
  }

  // 2️⃣ POSIX signal (works in WSL/WSA/Unix)
  try {
    process.on('SIGWINCH', poll);
  } catch {}

  // 3️⃣ fallback polling – covers current Bun on Windows & CI
  setInterval(poll, pollMs);

  // initial
  fire();
}