The galaxy-streams module provides a simple API to work with node.js streams. It contains wrappers for all the main streams of the node API, as well as generic ReadableStream and WritableStream wrappers.

Readable Streams

Once you have wrapped a readable stream, you can read from it with:

var data = yield stream.read(size);

The size parameter is optional. If you pass it and if the stream does not end prematurely, the read call returns a string/Buffer of exactly size characters / bytes. If the stream ends before size characters / bytes, the remaining data is returned. If you try to read past the end of the stream, null is returned.

Without size argument, read returns the next chunk of data available from the stream, as a string or Buffer depending on encoding. It returns null at the end of the stream.

Readable streams also support a synchronous unread(data) method, which is handy for parsers.

Writable Streams

Writable streams are similar. Once you have wrapped a writable stream, you can write to it with:

yield stream.write(data, encoding);

Encoding is optional. For a binary stream, you do not pass any encoding and data is a Buffer. For a character stream, you must pass an encoding and data is a string.

To end a stream, just write null or undefined. For example: yield stream.write();. You can also end it with a synchronous stream.end() call.