Using a HTTP request as a stream

http-request-to-stream.js

const request = http.request(opts)

// We expect a single response event to be emitted when the response
// to the request is received.
const response$ = _('response', request).head()

// Create an error stream from the error events from the request.
// As this is an event stream it is considered an infinite stream.
const error$ = _('error', request).map(error => { throw error })

// As such we need to know when the error stream is considered
// ended. We expect a single end event to be emitted from the
// response and will use this to end the error stream.
const end$ = response$.observe()
  .flatMap(response => _('end', response))
  .head()
  .done(_ => error$.end())
  
// As the response itself is a readable stream we simply flatMap
// it through Highland.js to retrieve the data buffers
const buffer$ = response$.flatMap(_)

// To parse a JSON request
const data$ = buffer$
  .map(buffer => buffer.toString('utf-8'))
  // BEWARE: all buffers will be collected up in memory... This
  // works for a generic JSON response, if you are parsing
  // extremely long JSON feeds of items and are memory constrained,
  // you could instead create or use a custom parser to emit
  // elements as they are encountered.
  .collect()
  .map(parts => parts.join(''))
  .map(JSON.parse)

// The parsed data and any errors as a single stream
const result$ = _([ data$, error$ ]).merge()