hasComparator property

bool get hasComparator

Whether this controller sorts siblings with a comparator.

Exists because reading comparator itself through a covariantly-typed reference (TreeController<TKey, Object?>, how TreeReorderController holds its controller) throws a runtime TypeError whenever a comparator is actually set: the comparator's function type uses TData contravariantly, so a non-null value fails the implicit covariance check on the read. (A null comparator reads fine, null inhabits every nullable type, which makes the failure mode data-dependent and easy to miss.) A bool carries no TData and is safe from any reference type.

Implementation

bool get hasComparator {
  return comparator != null;
}