better-emit-stream

Turn event emitters into streams and streams into event emitters.

This is a fork of the awesome emit-stream module from substack. It makes it bi-directional, so you can convert streams/emitters which you can read from OR write to.

example

write a server that streams an event emitter's events to clients:

var emitStream = require('emit-stream');
var JSONStream = require('JSONStream');
var net = require('net');

var server = (function () {
    var ev = createEmitter();
    
    return net.createServer(function (stream) {
        emitStream(ev)
            .pipe(JSONStream.stringify())
            .pipe(stream)
        ;
    });
})();
server.listen(5555);

var EventEmitter = require('events').EventEmitter;

function createEmitter () {
    var ev = new EventEmitter;
    setInterval(function () {
        ev.emit('ping', Date.now());
    }, 2000);
    
    var x = 0;
    setInterval(function () {
        ev.emit('x', x ++);
    }, 500);
    
    return ev;
}

then re-constitute the event-emitters on the client:

var emitStream = require('emit-stream');
var net = require('net');

var stream = net.connect(5555)
    .pipe(JSONStream.parse([true]))
;
var ev = emitStream(stream);

ev.on('ping', function (t) {
    console.log('# ping: ' + t);
});

ev.on('x', function (x) {
    console.log('x = ' + x);
});

$ node example/emit.js 
x = 0
x = 1
x = 2
x = 3
# ping: 1346116850523
x = 4
x = 5
^C

methods

var emitStream = require('emit-stream')

emitStream(x)

If x is a stream, returns an event emitter from emit.toStream(x).

Otherwise returns a stream from emit.fromStream(x).

emitStream.toStream(emitter)

Return a stream from the EventEmitter emitter.

The 'data' emitted by this stream will be array data. Serialization is up to you. I recommend JSONStream for most purposes.

emitStream.fromStream(stream)

Return an EventEmitter from stream.

The 'data' written to this stream should be an array, like JSONStream creates.

install

With npm do:

npm install emit-stream

license

MIT