WeakEventEmitter

WeakEventEmitter is a high performance event emitter with WEAK REFERENCES! It has been micro-optimized for various of code paths making this, one of, if not the fastest WeakEventEmitter available for Node.js and browsers. The module is API compatible with the WeakEventEmitter that ships by default with Node.js but there are some slight differences:

• Domain support has been removed.
• We do not throw an error when you emit an error event and nobody is listening.
• The newListener and removeListener events have been removed as they are useful only in some uncommon use-cases.
• The setMaxListeners, getMaxListeners, prependListener and prependOnceListener methods are not available.
• Support for custom context for events so there is no need to use fn.bind.
• The removeListener method removes all matching listeners, not only the first.

It's a drop in replacement for existing EventEmitters, but just faster. Free performance, who wouldn't want that? The WeakEventEmitter is written in EcmaScript 3 so it will work in the oldest browsers and node versions that you need to support.

Installation

$ npm install --save weakeventemitter

Usage

After installation the only thing you need to do is require the module:

var WeakEventEmitter = require('weakeventemitter');

And you're ready to create your own WeakEventEmitter instances. For the API documentation, please follow the official Node.js documentation:

http://nodejs.org/api/events.html

Contextual emits

We've upgraded the API of the WeakEventEmitter.on, WeakEventEmitter.once and WeakEventEmitter.removeListener to accept an extra argument which is the context or this value that should be set for the emitted events. This means you no longer have the overhead of an event that required fn.bind in order to get a custom this value.

var EE = new WeakEventEmitter()
  , context = { foo: 'bar' };

function emitted() {
  console.log(this === context); // true
}

EE.once('event-name', emitted, context);
EE.on('another-event', emitted, context);
EE.removeListener('another-event', emitted, context);

Tests and benchmarks

This module is well tested. You can run:

• npm test to run the tests under Node.js.
• npm run test-browser to run the tests in real browsers via Sauce Labs.

We also have a set of benchmarks to compare WeakEventEmitter with some available alternatives. To run the benchmarks run npm run benchmark.

Tests and benchmarks are not included in the npm package. If you want to play with them you have to clone the GitHub repository. Note that you will have to run an additional npm i in the benchmarks folder before npm run benchmark.

License

MIT