75lb/stream-connect

Connects an arbitrary number of streams into a single, combined stream

stream-connect

Similar to .pipe except .pipe returns the last stream in a pipeline. stream-connect returns a stream which writes to the first stream in the pipeline and reads from the last.

Synopsis

const connect = require('stream-connect')
const fs = require('fs')

const connected = connect(stream1, stream2, stream3, stream4)

// data piped into the connected stream is transparently passed through all four internal streams
// then output into process.stdout. Errors in any of the internal streams are emitted
// by the connected stream.
process.stdin
  .pipe(connected)
  .on('error', console.error)
  .pipe(process.stdout)

More detail

Consider this .pipe example.

function getExampleStream () {
 ...
 return streamOne.pipe(streamTwo)
}
const stream = getExampleStream()
stream.on('data', function (chunk) {}) // catches data from streamOne via streamTwo
stream.on('error', function (err) {}) // catches errors only from streamTwo
stream.end('test') // is written to streamTwo

If you write to the output it will be written to streamTwo, whereas you probably wanted to write to the start of the pipeline and read from the end. Fixed by stream-connect:

const connect = require('stream-connect')
function getExampleStream () {
 ...
 return connect(streamOne, streamTwo)
}
const stream = getExampleStream()
stream.on('data', function (chunk) {}) // catches data from streamOne via streamTwo
stream.on('error', function (err) {}) // catches errors from both streamOne and streamTwo
stream.end('test') // is written to streamOne

Any errors emitted in streamOne or streamTwo are propagated to the output stream.

stream-connect

Example

const connect = require('stream-connect')

connect(...streams) ⇒ Duplex ⏏

Connect streams.

Kind: Exported function

Param	Type	Description
...streams	Duplex	One or more streams to connect.

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© 2015 Lloyd Brookes <[email protected]>. Documented by jsdoc-to-markdown.

stream-connect's Issues

write tests and docs to show how errors are propagated