events 
Node’s event emitter for all engines.
This implements the Node.js [events][node.js docs]
module for environments that do not have it, like browsers.
eventscurrently matches the Node.js 11.13.0 API.
Note that the events module uses ES5 features. If you
need to support very old browsers like IE8, use a shim like es5-shim.
You need both the shim and the sham versions of
es5-shim.
This module is maintained, but only by very few people. If you’d like to help, let us know in the Maintainer Needed issue!
Install
You usually do not have to install events yourself! If
your code runs in Node.js, events is built in. If your code
runs in the browser, bundlers like browserify or webpack also include the
events module.
But if none of those apply, with npm do:
npm install eventsUsage
var EventEmitter = require('events')
var ee = new EventEmitter()
ee.on('message', function (text) {
console.log(text)
})
ee.emit('message', 'hello world')API
See the [Node.js EventEmitter docs][node.js docs].
events currently matches the Node.js 11.13.0 API.
Contributing
PRs are very welcome! The main way to contribute to
events is by porting features, bugfixes and tests from
Node.js. Ideally, code contributions to this module are copy-pasted from
Node.js and transpiled to ES5, rather than reimplemented from scratch.
Matching the Node.js code as closely as possible makes maintenance
simpler when new changes land in Node.js. This module intends to provide
exactly the same API as Node.js, so features that are not available in
the core events module will not be accepted. Feature
requests should instead be directed at nodejs/node and will be added
to this module once they are implemented in Node.js.
If there is a difference in behaviour between Node.js’s
events module and this module, please open an issue!
License
MIT [node.js docs]: https://nodejs.org/dist/v11.13.0/docs/api/events.html