from2 
from2 is a high-level module for creating readable streams that properly handle backpressure.
Convience wrapper for
readable-stream's ReadableStream
base class, with an API lifted from
from and
through2.
Usage
stream = from2([opts], read)
Where opts are the options to pass on to the ReadableStream constructor,
and read(size, next) is called when data is requested from the stream.
sizeis the recommended amount of data (in bytes) to retrieve.next(err)should be called when you're ready to emit more data.
For example, here's a readable stream that emits the contents of a given
string:
var from = require('from2')
function fromString(string) {
return from(function(size, next) {
// if there's no more content
// left in the string, close the stream.
if (string.length <= 0) return next(null, null)
// Pull in a new chunk of text,
// removing it from the string.
var chunk = string.slice(0, size)
string = string.slice(size)
// Emit "chunk" from the stream.
next(null, chunk)
})
}
// pipe "hello world" out
// to stdout.
fromString('hello world').pipe(process.stdout)
stream = from2.obj([opts], read)
Shorthand for from2({ objectMode: true }, read).
createStream = from2.ctor([opts], read)
If you're creating similar streams in quick succession you can improve
performance by generating a stream constructor that you can reuse instead
of creating one-off streams on each call.
Takes the same options as from2, instead returning a constructor which you
can use to create new streams.
See Also
- from2-array - Create a from2 stream based on an array of source values.
- from2-string - Create a stream from a string. Sugary wrapper around from2.
License
MIT. See LICENSE.md for details.