recurve-signal

Custom event/messaging library for the browser and Node.js. Inspired by AS3 signals library.

Similar to other event dispatching mechanisms such as event emitters, or buses. But instead of registering for events by string name you register on a signal object responsible for one event.

Usage

Example

var started = new Signal();

// Add some listeners
started.on(onStartA);
started.on(onStartB);

// Trigger the signal. onStartA and onStartB will be called with "oh ya" as
// the message
started.trigger("oh ya");

// Remove a listener
started.off(onStartA);

// onStartA will not be called, but onStartB will be called
started.trigger("oh no");

For more examples, take a look at the unit tests

Creating a Signal

Signal()

var started = new Signal();

Adding Listeners

on(callback, context)

Add a listener. The callback will be called each time the signal is triggered.

If a listener for the callback and context already exists then this method will do nothing. Duplicate listeners will not be added.

var started = new Signal();
signal.on(onStart, this);

function onStart() {
}

once(callback, context)

Adds a listener callback that will only be called once and will then be removed.

If a listener for the callback and context already exists then this method will do nothing. Duplicate listeners will not be added.

var started = new Signal();
signal.once(onStart, this);

function onStart() {
}

started.trigger(); // onStart will be called and then removed as a listener
started.trigger(); // onStart will not be called

Trigger Signal

trigger()

Triggers the signal. Arguments passed into the method will be passed as parameters to all listeners

var signal = new Signal();
signal.on(function(message) {
    // will be called with "oh ya" as the message
});

signal.trigger("oh ya");

Removing Listeners

off(callback, context)

If a callback and context are specified then the listener with matching callback and context is removed

var started = new Signal();
signal.on(onStartA, this);
signal.on(onStartB, this);
signal.off(onStartA, this); // only onStartA will be removed

If only a callback is specified then the listener with matching callback is removed

var started = new Signal();
signal.on(onStartA, this);
signal.on(onStartB, this);
signal.off(onStartA); // only onStartA will be removed

If only a context is specified then all listeners with the matching context are removed

var started = new Signal();
signal.on(onStartA, this);
signal.on(onStartB, this);
signal.on(onStartC);
signal.off(null, this); // onStartA and onStartB will be removed

If no callback or context are specified then all listeners are removed (equivalent to clear)

var started = new Signal();
signal.on(onStartA, this);
signal.on(onStartB, this);
signal.on(onStartC);
signal.off(); // onStartA, onStartB, and onStartC will be removed

clear()

var started = new Signal();
signal.on(onStart);
signal.clear();

Disabling

disable(value)

Disable or enable listeners from being called when the signal is triggered.

var signal = new Signal();
signal.on(onStart);
signal.disable();

signal.trigger(); // onStart will not be called
signal.disable(false);
signal.trigger(); // onStart will be called

Running the Tests

grunt test

Installation

The library is UMD compliant. Registers on window.Signal for global.

npm install recurve-signal

Browser Support

IE6+

License

The MIT License (MIT)

Copyright (c) 2015 Sebastien Couture

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.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.