Iterator concat not supported


I am upgrading from version 1.7.25 to 2.0.8, and I found out that some functionality like concat supported by Iterator before is now removed.
What is the reason behind this and what can we do to best replicate the behavior?


When moving to TypeScript there were incompatibilities between Iterator types, because the Map iterator is different from the others, which made enforcing internal ConcatIterator types somewhat difficult. At that time we decided to remove concat since it was unused internally and not documented.

Unfortunately, we do not have a drop-in replacement. Most of the relevant functions simply operate on one iterator and then the next. For example:

ConcatIterator.prototype.each = function(func) {
  return this;

Thanks for the explanation!