pre method

  1. @nonVirtual
void pre({
  1. required bool condition(),
  2. required String message(),
})

Checks a precondition.

Evaluates condition once when checks are enabled and evaluates message only when it fails. In ContractCheckingMode.assertionsOnly, a failed condition triggers an assertion; in ContractCheckingMode.alwaysThrow, it throws a ContractViolationError with kind ViolationKind.preCondition.

Implementation

@nonVirtual
void pre({
  required bool Function() condition,
  required String Function() message,
}) => _evaluate(kind: .preCondition, condition: condition, message: message);