asyncReduce<T, TAcc> function

Future<TAcc> asyncReduce<T, TAcc>(List<T> items, Future<TAcc> selector(TAcc acc, T item), TAcc seed)

Reduces a list using an asynchronous selector function.

Like Iterable.fold, but each step is asynchronous. Items are processed sequentially, with each step waiting for the previous one to complete.

items - The input list to reduce. selector - The async reducer function that takes the accumulator and current item, returning the new accumulator value. seed - The initial value for the accumulator.

Returns the final accumulated value.

Example:

final input = [1, 2, 3, 4, 5];
final sum = await asyncReduce(
  input,
  (acc, x) async => acc + x,
  0,
);
// sum: 15

Implementation

Future<TAcc> asyncReduce<T, TAcc>(
  List<T> items,
  Future<TAcc> Function(TAcc acc, T item) selector,
  TAcc seed,
) async {
  var acc = seed;
  for (final item in items) {
    acc = await selector(acc, item);
  }
  return acc;
}