JavaScript infinite streams

This post was heavily inspired by this post: Infinite Data structures in Javascript  (author: Dimitris Papadimitriou)

After reading the article, I also wanted to have the bare minimum, and most simple implementation of a Stream - and surprisingly, it is very easy (in terms of code), but also, kinda complicated. Kind of the sweetspot I really like to learn about!

In this implementation, we add a filter method to the stream object, which takes a predicate function pred and returns a new stream object with only the elements that pass the predicate. If the current value passes the predicate, then the resulting stream will include the current value and the result of calling filter on the next property. Otherwise, the resulting stream will only include the result of calling filter on the next property. If there is no next property, then the emptyStream object is returned.

The resulting mappedStream is a stream of strings with the same structure as the original stream, but with each element converted to a string. The resulting filteredStream is a stream with only the elements that are greater than 1.