Helper functions for streams in node js.

$3

``
import { map } from 'stream-function'
somestream.pipe(map(somefunction))
`

$3

`
import { filter } from 'stream-function'
somestream.pipe(filter(somefunction))
`

$3

`
import { flatten } from 'stream-function'
somestream.pipe(flatten())
`

$3

`
import { buffer } from 'stream-function'
somestream.pipe(buffer(buffersize))
`

$3

`
import { map } from 'stream-function'
somestream.pipe(promiseMap(somepromisefunction))
``