readable.pipe returns stream.Readable

[andreasg123]

readable.pipe is documented to return stream.Writable. However, as only stream.Readable has a pipe method, it only makes sense to return that to set up chains of piped streams. I also verified that a pipe to a Gunzip object could be used as a Readable stream.

[addaleax]

Hi! Can you explain what you are asking here? While everything you said is accurate, it’s not clear what you would like to see changed (if anything).

Chaining pipes using this method only makes sense if the target Writable also implements the Readable interface, yes. For Gunzip streams, or generally Duplex streams, that is the case.

If the returned value is not a Readable instance, then chaining pipes won’t work, but it’s still a meaningful thing and may be helpful to have (e.g. event listeners can be installed on it).

I think changing what .pipe() returns would be too big of a breaking change, in case that’s what you are suggesting here.

[andreasg123]

I'm only asking to make the documentation a little clearer. I guess I should have checked the code to determine that the destination parameter to pipe is just the return value (currently not documented). I think that it would be beneficial to document explicitly that chaining pipes only works if the target Writable also implements the Readable interface. In the current documentation, it is confusing to understand why returning a Writable would support chaining.

It would also be helpful to document that Gunzip implements both Readable and Writable. That's kind of implied but there is no documentation on the methods of this class or its siblings.