GroupAdjacentFunc in Golang

group.go

func GroupAdjacentFunc[T any, K comparable](seq iter.Seq[T], by func(item T) K) iter.Seq[[]T] {
	return func(yield func([]T) bool) {
		var group []T
		var groupKey K
		for item := range seq {
			key := by(item)
			if key == groupKey {
				group = append(group, item)
			} else {
				if len(group) > 0 && !yield(group) {
					return // stop iteration
				}
				group = []T{item}
				groupKey = key
			}
		}
		if len(group) > 0 {
			_ = yield(group)
		}
	}
}