Asynchronous cancelable (or not) EventEmitter-like object
An EventEmitter replacement that allows the library to make events cancelable by the event handlers and allows event handlers to be synchronous or asynchronous.
npm install async-cancelable-events
var EventEmitter = require'async-cancelable-events';var util = require'util';EventEmittercallthis;utilinheritsMyEmittingObject EventEmitter;
The API is intented to be a mostly-drop-in replacement for Node.js' EventEmitter object, with a little bit of DOM Events and more asynchronicity sprinkled in.
The primary differences between the EventEmitter and async-cancelable-events are:
- If the last argument passed into
this.emitis a function, it is assumed to be a callback that accepts a boolean indicating whether to continue the event (
true) or cancel it (
.oncemethods try to "guess" if the provided handler is synchronous or asynchronous (based on its argument length), or can be explicitly registered as synchronous or asynchronous with
- Passing the maximum number of listeners allowed will fire off a
maxListenersPassedevent with the event name and listener count as arguments. The warning the official
EventEmitterprints is simply a listener for
async-cancelable-events, and can be disabled by running
this.removeAllListeners('maxListenersPassed')just after the
- The various method calls are chainable, so
foo.on('bar', func1).on('baz', func2)is valid.
Copyright (C) 2012-2013 by David Ellis
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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