If Node's EventEmitter and Eve were to have a child, it might look something like this. No wildcard support at this stage though...
Displayed below is a simple example:
var bus = require('mbus')();
bus.on('foo.bar', function() {
console.log('foo.bar triggered');
});
bus('foo.bar');
OUTPUT:
foo.bar triggered
Another simple example demonstrates, how a message bus can be provided a parent message bus to relay messages to once after any local handlers have been invoked:
var bus = require('mbus')();
var foo = require('mbus')('foo', bus);
bus.on('foo.bar', function() {
console.log('foo.bar triggered');
});
foo.on('bar', function() {
console.log('foo triggered bar');
});
foo('bar');
OUTPUT:
foo triggered bar
foo.bar triggered
By default, events are emitted with a dot delimited format which respects their lineage. A good example of this is the second example shown above.
It is not mandatory for a child bus to add it's own namespace when events are invoked, however, as the bus can be created with an empty namespace:
var bus = require('mbus')();
var foo = require('mbus')('', bus);
bus.on('bar', function() {
console.log('bar triggered at parent level');
});
foo.on('bar', function() {
console.log('foo triggered bar');
});
foo('bar');
OUTPUT:
foo triggered bar
bar triggered at parent level
This can be very useful when you want to unify events into a single event bus but distribute their creation across a number of packages.
In some situations, it is more desirable to get information on all the events that are passing through a bus rather than attempting to intercept individual events. This behaviour can be done using mbus via the feed
function:
var bus = require('mbus')();
var stopFeed = bus.feed(function(evt) {
console.log('received event name: ' + evt.name + ', with args: ', evt.args);
});
// trigger some events
bus('foo', 'hello', 'there');
bus('bar');
// terminate the feed
stopFeed();
// won't be logged as the feed has been stopped
bus('baz');
OUTPUT:
received event name: foo, with args: [ 'hello', 'there' ]
received event name: bar, with args: []
Additionally, feeds can be attached to a bus parent to capture namespaced events:
var bus = require('mbus')();
var foo = require('mbus')('foo', bus);
var stopFeed = bus.feed(function(evt) {
console.log('received event name: ' + evt.name + ', with args: ', evt.args);
});
// trigger some events
foo('bar', 'hello', 'there');
foo('baz');
OUTPUT:
received event name: foo.bar, with args: [ 'hello', 'there' ]
received event name: foo.baz, with args: []
Create a new message bus with namespace
inheriting from the parent
mbus instance. If events from this message bus should be triggered with
a specific this
scope, then specify it using the scope
argument.
Reset the handler registry, which essential deregisters all event listeners.
Alias: removeAllListeners
Attach a handler function that will see all events that are sent through this bus in an "object stream" format that matches the following format:
{ name: 'event.name', args: [ 'event', 'args' ] }
The feed function returns a function that can be called to stop the feed sending data.
Deregister an event handler.
Register an event handler for the event name
.
Register an event handler for the event name
that will only
trigger once (i.e. the handler will be deregistered immediately after
being triggered the first time).
Copyright (c) 2014 Damon Oehlman damon.oehlman@gmail.com
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