static bool _isBlockFunction()

in lib/src/argument_list_visitor.dart [229:268]

• 24 lines of code
• 13 McCabe index (conditional complexity)

  static bool _isBlockFunction(Expression expression) {
    if (expression is NamedExpression) expression = expression.expression;

    // Allow functions wrapped in dotted method calls like "a.b.c(() { ... })".
    if (expression is MethodInvocation) {
      if (!_isValidWrappingTarget(expression.target)) return false;
      if (expression.argumentList.arguments.length != 1) return false;

      return _isBlockFunction(expression.argumentList.arguments.single);
    }

    if (expression is InstanceCreationExpression) {
      if (expression.argumentList.arguments.length != 1) return false;

      return _isBlockFunction(expression.argumentList.arguments.single);
    }

    // Allow immediately-invoked functions like "() { ... }()".
    if (expression is FunctionExpressionInvocation) {
      if (expression.argumentList.arguments.isNotEmpty) return false;

      expression = expression.function;
    }

    // Unwrap parenthesized expressions.
    while (expression is ParenthesizedExpression) {
      expression = expression.expression;
    }

    // Must be a function.
    if (expression is! FunctionExpression) return false;

    // With a curly body.
    if (expression.body is! BlockFunctionBody) return false;

    // That isn't empty.
    var body = expression.body as BlockFunctionBody;
    return body.block.statements.isNotEmpty ||
        body.block.rightBracket.precedingComments != null;
  }