Function getProjectSearchDir

src/bin.ts:689–732

* Get project search path from args.

(
  cwd?: string,
  scriptMode?: boolean,
  cwdMode?: boolean,
  scriptPath?: string
)

 * Get project search path from args.
 */
function getProjectSearchDir(
  cwd?: string,
  scriptMode?: boolean,
  cwdMode?: boolean,
  scriptPath?: string
) {
  // Validate `--script-mode` / `--cwd-mode` / `--cwd` usage is correct.
  if (scriptMode && cwdMode) {
    throw new TypeError('--cwd-mode cannot be combined with --script-mode');
  }
  if (scriptMode && !scriptPath) {
    throw new TypeError(
      '--script-mode must be used with a script name, e.g. `ts-node --script-mode <script.ts>`'
    );
  }
  const doScriptMode =
    scriptMode === true ? true : cwdMode === true ? false : !!scriptPath;
  if (doScriptMode) {
    // Use node's own resolution behavior to ensure we follow symlinks.
    // scriptPath may omit file extension or point to a directory with or without package.json.
    // This happens before we are registered, so we tell node's resolver to consider ts, tsx, and jsx files.
    // In extremely rare cases, is is technically possible to resolve the wrong directory,
    // because we do not yet know preferTsExts, jsx, nor allowJs.
    // See also, justification why this will not happen in real-world situations:
    // https://github.com/TypeStrong/ts-node/pull/1009#issuecomment-613017081
    const exts = ['.js', '.jsx', '.ts', '.tsx'];
    const extsTemporarilyInstalled: string[] = [];
    for (const ext of exts) {
      if (!hasOwnProperty(require.extensions, ext)) {
        extsTemporarilyInstalled.push(ext);
        require.extensions[ext] = function () {};
      }
    }
    try {
      return dirname(requireResolveNonCached(scriptPath!));
    } finally {
      for (const ext of extsTemporarilyInstalled) {
        delete require.extensions[ext];
      }
    }
  }

  return cwd;
}

const guaranteedNonexistentDirectoryPrefix = resolve(__dirname, 'doesnotexist');
let guaranteedNonexistentDirectorySuffix = 0;