114 lines
3.9 KiB
Markdown
114 lines
3.9 KiB
Markdown
# Ultron
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[](http://unshift.io)[](http://browsenpm.org/package/ultron)[](https://travis-ci.org/unshiftio/ultron)[](https://david-dm.org/unshiftio/ultron)[](https://coveralls.io/r/unshiftio/ultron?branch=master)[](http://webchat.freenode.net/?channels=unshift)
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Ultron is a high-intelligence robot. It gathers intelligence so it can start
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improving upon his rudimentary design. It will learn your event emitting
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patterns and find ways to exterminate them. Allowing you to remove only the
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event emitters that **you** assigned and not the ones that your users or
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developers assigned. This can prevent race conditions, memory leaks and even file
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descriptor leaks from ever happening as you won't remove clean up processes.
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## Installation
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The module is designed to be used in browsers using browserify and in Node.js.
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You can install the module through the public npm registry by running the
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following command in CLI:
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```
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npm install --save ultron
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```
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## Usage
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In all examples we assume that you've required the library as following:
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```js
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'use strict';
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var Ultron = require('ultron');
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```
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Now that we've required the library we can construct our first `Ultron` instance.
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The constructor requires one argument which should be the `EventEmitter`
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instance that we need to operate upon. This can be the `EventEmitter` module
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that ships with Node.js or `EventEmitter3` or anything else as long as it
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follow the same API and internal structure as these 2. So with that in mind we
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can create the instance:
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```js
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//
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// For the sake of this example we're going to construct an empty EventEmitter
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//
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var EventEmitter = require('events').EventEmitter; // or require('eventmitter3');
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var events = new EventEmitter();
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var ultron = new Ultron(events);
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```
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You can now use the following API's from the Ultron instance:
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### Ultron.on
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Register a new event listener for the given event. It follows the exact same API
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as `EventEmitter.on` but it will return itself instead of returning the
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EventEmitter instance. If you are using EventEmitter3 it also supports the
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context param:
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```js
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ultron.on('event-name', handler, { custom: 'function context' });
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```
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Just like you would expect, it can also be chained together.
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```js
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ultron
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.on('event-name', handler)
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.on('another event', handler);
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```
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### Ultron.once
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Exactly the same as the [Ultron.on](#ultronon) but it only allows the execution
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once.
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Just like you would expect, it can also be chained together.
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```js
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ultron
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.once('event-name', handler, { custom: 'this value' })
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.once('another event', handler);
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```
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### Ultron.remove
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This is where all the magic happens and the safe removal starts. This function
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accepts different argument styles:
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- No arguments, assume that all events need to be removed so it will work as
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`removeAllListeners()` API.
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- 1 argument, when it's a string it will be split on ` ` and `,` to create a
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list of events that need to be cleared.
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- Multiple arguments, we assume that they are all names of events that need to
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be cleared.
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```js
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ultron.remove('foo, bar baz'); // Removes foo, bar and baz.
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ultron.remove('foo', 'bar', 'baz'); // Removes foo, bar and baz.
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ultron.remove(); // Removes everything.
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```
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If you just want to remove a single event listener using a function reference
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you can still use the EventEmitter's `removeListener(event, fn)` API:
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```js
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function foo() {}
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ultron.on('foo', foo);
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events.removeListener('foo', foo);
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```
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## License
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MIT
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