foldRightIndexed<S> method Null safety

S foldRightIndexed<S>(
  1. S initial,
  2. IndexedReversedAccumulate<S, E> f
)

Accumulates a collection to a single value, which starts from an initial value, by combining each element with the current accumulator value, with the combinator f in a reversed order, providing sequential index of the element.

It's the index-aware version of foldRight(). Caution: to reverse an Iterable may cause performance issue, see sdk#26928

Implementation

S foldRightIndexed<S>(S initial, IndexedReversedAccumulate<S, E> f) {
  final list = asList();
  final len = list.length;
  var acc = initial;
  for (var i = len - 1; i >= 0; i--) {
    acc = f(i, list[i], acc);
  }
  return acc;
}