require function

void require(
  1. bool value, [
  2. dynamic message
])

message should be null, String or String Function()

Implementation

void require(final bool value, [final dynamic message]) {
  if (!value) {
    String? m;
    if (message is String?) {
      m = message;
    } else if (message is String Function()) {
      m = message();
    } else {
      throw InternalSealedError('message type is invalid');
    }
    throw SealedError(m);
  }
}