Function hasCommandOnPath

src/engine.ts:50–82

(
  bin: string,
  env: NodeJS.ProcessEnv = process.env,
  platform = process.platform,
)

// ── Detection ──────────────────────────────────────────────────────────

export function hasCommandOnPath(
  bin: string,
  env: NodeJS.ProcessEnv = process.env,
  platform = process.platform,
): boolean {
  const searchPath = env.PATH ?? '';
  const pathDirs = searchPath.split(path.delimiter).filter(Boolean);
  const pathext = (env.PATHEXT ?? '.EXE;.CMD;.BAT;.COM')
    .split(';')
    .map((ext) => ext.trim())
    .filter(Boolean);

  const hasPathSeparator = /[\\/]/.test(bin);
  const baseCandidates = hasPathSeparator
    ? [bin]
    : pathDirs.map((dir) => path.join(dir, bin));
  const candidates = platform === 'win32'
    ? baseCandidates.flatMap((candidate) => {
        if (path.extname(candidate)) return [candidate];
        return pathext.map((ext) => `${candidate}${ext}`);
      })
    : baseCandidates;

  return candidates.some((candidate) => {
    try {
      if (platform === 'win32') return fs.statSync(candidate).isFile();
      fs.accessSync(candidate, fs.constants.X_OK);
      return true;
    } catch {
      return false;
    }
  });
}

export function detectAvailableEngines(): string[] {
  return PREFERENCE_ORDER.filter((name) => hasCommandOnPath(KNOWN_ENGINES[name].bin));