I believe a transducer could be a feature of a lazy sequence. But a lazy sequence does not guarantee the process is using a transducer.
I just checked lazy.js and it seems like it does support this.
What’s important here is that no iteration takes place until you call
each, and no intermediate arrays are created. Essentially Lazy.js combines all query operations into a sequence that behaves quite a bit like the procedural code we wrote a moment ago. (If you ever do want an array, simply call
toArrayon the resulting sequence.)