runWithConsoleMarkdown<T> function

Future<T> runWithConsoleMarkdown<T>(Future<T> body(), { void onError(Object error, StackTrace stack)?, })

Run body inside a Dart zone that automatically renders console_markdown syntax in every print() call.

If the current zone already has console_markdown active (detected via kConsoleMarkdownZoneKey), body runs directly without adding another rendering layer — this prevents double-rendering when tools are invoked from contexts that already set up the zone (e.g. tom_d4rt_dcli).

The optional onError callback handles uncaught errors. By default, errors are printed to stderr with console_markdown formatting and the process exits with code 1.

Returns the value returned by body.

Implementation

Future<T> runWithConsoleMarkdown<T>(
  Future<T> Function() body, {
  void Function(Object error, StackTrace stack)? onError,
}) async {
  // Already inside a console_markdown zone → pass through.
  if (isConsoleMarkdownActive) {
    return body();
  }

  final completer = Completer<T>();

  runZonedGuarded(
    () async {
      try {
        final result = await body();
        if (!completer.isCompleted) completer.complete(result);
      } catch (error, stack) {
        if (!completer.isCompleted) completer.completeError(error, stack);
      }
    },
    (error, stack) {
      if (onError != null) {
        onError(error, stack);
      } else {
        stderr.writeln('<red>**Uncaught error:**</red> $error'.toConsole());
        stderr.writeln(stack.toString());
        exit(1);
      }
      if (!completer.isCompleted) {
        completer.completeError(error, stack);
      }
    },
    zoneSpecification: ZoneSpecification(
      print: (Zone self, ZoneDelegate parent, Zone zone, String line) {
        parent.print(zone, line.toConsole());
      },
    ),
    zoneValues: {kConsoleMarkdownZoneKey: true},
  );

  return completer.future;
}