StreamEmitter

This module takes the easy interface of EventEmitters and replaces callbacks with streams. After wrapping a source emitter you can turn any events related to it into streams, and can pipe streams to emit events on data.

Installing

npm install --save streamemitter

API

StreamEmitter([eventemitter])

Constructs a new StreamEmitter and wraps over the given eventemitter and uses it for creating streams. If no eventemitter is provided, one is created behind the scenes

StreamEmitter#on(event)

Returns a readable stream which receives data every time event is emitted on the eventemitter

StreamEmitter#emit(event)

Returns a writable stream which emits any data passed in on the eventemitter with the given event.

StreamEmitter#synchronize

A duplex stream that can be used for synchronizing instances of StreamEmitter

Note: Currently only events that are emitted using the StreamEmitter#emit method can be synchronized. The alternative would require that the eventemitter's emit method gets patched, which may not always be desirable.

Example

var StreamEmitter = require("streamemitter").StreamEmitter;
var EventEmitter = require("events").EventEmitter;
 
var events = new EventEmitter();
var streams = new StreamEmitter(events);
 
// Relay all `message` events to STDOUT
streams.on("message").pipe(process.stdout);
 
// Relay all `message` events into `message2` using the writable stream from emit
streams.on("message").pipe(streams.emit("message2"));
 
// Relay all `message2` events to STDOUT as well
streams.on("message2").pipe(process.stdout);
 
var times = 5;
var interval = setInterval(function () {
  // Emit an event on the original event listener
  events.emit("message", "Ping:" + times + "\n");
  times--;
  if (!times) clearInterval(interval);
}, 1000);

Synchronization example

var StreamEmitter = require("streamemitter").StreamEmitter;
var StreamArray = require("stream-array");
var stdout = require("stdout");
 
var e1 = new StreamEmitter();
var e2 = new StreamEmitter();
 
e1.synchronize.pipe(e2.synchronize).pipe(e1.synchronize);
 
e2.on("message").pipe(stdout());
StreamArray(["a", "b", "c", "d"]).pipe(e1.emit("message"));