ordered-emitter

Buffer events that may arrive out of order so that they are emitted in order.
Just emit event objects with an "order" key starting at 0.

emit.js

var OrderedEmitter = require('ordered-emitter');
var em = new OrderedEmitter;

em.on('beep', function (obj) {
    console.dir(obj);
});

var objects = [
    { order : 1 },
    { order : 2 },
    { order : 4 },
    { order : 0 },
    { order : 3 },
];

var iv = setInterval(function () {
    var obj = objects.shift();
    if (!obj) clearInterval(iv)
    else em.emit('beep', obj)
}, 500);

output:

{ order: 0 }
{ order: 1 }
{ order: 2 }
{ order: 3 }
{ order: 4 }

span.js

var OrderedEmitter = require('ordered-emitter');
var em = new OrderedEmitter({ span : true });

em.on('beep', function (obj) {
    console.log('beep ' + obj.x);
});

em.on('boop', function (obj) {
    console.log('boop ' + obj.x);
});

em.emit('beep', { order : 1, x : 'b' });
em.emit('beep', { order : 3, x : 'd' });
em.emit('boop', { order : 0, x : 'a' });
em.emit('beep', { order : 2, x : 'c' });
em.emit('boop', { order : 5, x : 'f' });
em.emit('boop', { order : 4, x : 'e' });

output:

boop a
beep b
beep c
beep d
boop e
boop f

var OrderedEmitter = require('ordered-emitter');

var em = new OrderedEmitter(opts={})

OrderedEmitter acts just like an EventEmitter, except that any event that emits objects as its first argument with numeric order keys will be buffered so that the events will be emitted in order.
By default, order keys are isolated by event names so the order keys from different event names won't influence each other. However, you can have order keys work across multiple event names by setting opts.span to true.

em.reset(eventName)

Reset the counter for an ordered emitter back to 0.
If eventName is undefined, reset all the counters to 0.

em.clear(eventName)

Clears the event queue for an ordered emitter.
If eventName is undefined, clear all the event queues.With npm do:

npm install ordered-emitter

MIT/X11