event-emitter3 fork of EventEmitter3
EventEmitter3 is a high performance EventEmitter. It has been micro-optimized for various of code paths making this, one of, if not the fastest EventEmitter available for Node.js. The module is API compatible with the EventEmitter that ships by default with Node.js but there are some slight differences:
- Domain support has been removed.
- We do not
throwan error when you emit an
errorevent and nobody is listening.
newListenerevent is removed as the use-cases for this functionality are really just edge cases.
setMaxListenersand its pointless memory leak warnings. If you want to add
endlisteners you should be able to do that without modules complaining.
listenersmethod can do existence checking instead of returning only arrays.
removeListenermethod 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 EventEmitter is written in EcmaScript 3 so it will work in the oldest browsers and node versions that you need to support.
$ npm install --save event-emitter3
After installation the only thing you need to do is require the module:
var EventEmitter = ;
And you're ready to create your own EventEmitter instances. For the API documentation, please follow the official Node.js documentation:
To check if there is already a listener for a given event you can supply the
listeners method with an extra boolean argument. This will transform the
output from an array, to a boolean value which indicates if there are listeners
in place for the given event:
var EE = ;EE;EE;EE; // returns trueEE; // returns false
Tests and benchmarks
This module is well tested. You can run:
npm testto run the tests under Node.js.
We also have a set of benchmarks to compare EventEmitter3 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.