LanguageFeatures/Spread-collections/NullAware_A01_t03.dart

// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/// @assertion To handle these gracefully, we support a [...?] "null-aware
/// spread" operator. In cases where the spread expression evaluates to [null],
/// that expands to an empty collection instead of throwing a runtime expression.
///
///  That turns the example to:
///
///   var command = [
///   engineDartPath,
///   '--target=flutter',
///   ...?extraFrontEndOptions,
///   mainPath
///   ];
/// @description Checks that spreadable element of the [Set] can be null-aware
/// and example from the Spec works correctly.
/// @author iarkh@unipro.ru


import "../../Utils/expect.dart";

Set getASet(
    String engineDartPath, List? extraFrontEndOptions, String mainPath) {
  return(
      {engineDartPath, '--target=flutter', ...?extraFrontEndOptions, mainPath});
}

main() {
  Expect.setEquals(
      {"enginePath", "--target=flutter", "--option1", "--option2", "mainPath"},
      getASet("enginePath", ["--option1", "--option2"], "mainPath"));
  Expect.setEquals({"enginePath", "--target=flutter", "mainPath"},
      getASet("enginePath", null, "mainPath"));
}