How does piping a stream back to itself work with Trumpet?

Question

Learning node.js. Trumpet works by piping a stream back to itself, apparently, so the processed data can then be output. This makes no sense to me, since it seems to be like c

Answer 1

I was confused too and i would express it again with my words:

tr.select('.loud').createStream() creates a Duplex-Stream which is nothing else than a combined ReadStream and WriteStream

This Stream recieves all matches in its ReadStream. If you write to the WriteStream, trumpet takes it as match-replace

This works for me in the same way:

// create trumpet stream
var tr = trumpet();

// create stream with selected elems
var trumpetSelector = tr.select('.loud');
var upperOut = trumpetSelector.createReadStream();
var upperIn = trumpetSelector.createWriteStream();
upperOut.pipe(new UpperCaseTransformer()).pipe(upperIn);

Please correct me if i'm wrong!