extended-emitter

An emitter with expanded utility, UMD with dependencies for node and the browser

Usage no npm install needed!

<script type="module">
  import extendedEmitter from 'https://cdn.skypack.dev/extended-emitter';
</script>

README

extended-emitter.js

NPM version npm Travis

Everything you expect from require('events').EventEmitter in both the browser and client, plus:

  • .allOff() : removes all events from this emitter
  • .emitter : the internal emitter used, in case you need direct access.

optional criteria

you can now using mongo-style queries (supported by sift) to subscribe to specific events (in this context .once() means meeting the criteria, not just firing an event of that type).

emitter.on('my_object_event', {
    myObjectId : object.id
}, function(){
    //do stuff here
});

or

emitter.once('my_object_event', {
    myObjectId : object.id,
    myObjectValue : {
        $gt : 20,
        $lt : 40
    }
}, function(){
    //do stuff here
});

.when()

and there's also the addition of a when function which can take ready-style functions, real promises or events, making it easy to delay or wait for a state, without resorting to chaining.

emitter.when([$(document).ready, 'my-init-event', 'my-load-event'], function(){
    //do stuff
});

.onto()

Often you want an object to implement emitters, and while it's easy enough to wrap them, why not just have that done for you and avoid the boilerplate?

emitter.onto(MyClass.prototype);
emitter.onto(MyInstance);
emitter.onto(MyObject);

or in the constructor:

emitter.onto(this);

Testing

Run the tests at the project root with:

mocha

Enjoy,

-Abbey Hawk Sparrow