expandLiveFileArguments function

List<String> expandLiveFileArguments(List<String> arguments)

Replaces arguments written as @path with the contents of that file, so an option can take a file: --scenario @seeds/jane.json.

Works for --option=@path too. Start a value with @@ when it really begins with @. Arguments after -- are left alone. Trailing newlines are dropped, as $(cat path) does. Throws a FormatException when the file doesn't exist.

Implementation

List<String> expandLiveFileArguments(List<String> arguments) {
  final List<String> expanded = [];
  for (int i = 0; i < arguments.length; i++) {
    final String argument = arguments[i];
    if (argument == '--') {
      expanded.addAll(arguments.sublist(i));
      break;
    }
    final int equals = argument.startsWith('--') ? argument.indexOf('=') : -1;
    expanded.add(
      equals == -1
          ? _fileValue(argument)
          : '${argument.substring(0, equals + 1)}'
                '${_fileValue(argument.substring(equals + 1))}',
    );
  }
  return expanded;
}