Subscribable.js

A tiny extendable JS constructor for custom event listening. Use it in the browser or in node:

Install

npm install subscribable.js

OR

bower install subscribable.js

Simple usage

var Daniel = new Subscribable();

Daniel.on('puke', function(event, msg) {
	console.log('Eeeww! ' + msg);
});

Daniel.trigger('puke', 'That was gross!');
//=> Eeeww! That was gross!

Add events to any constructor

In this example the Person contructor inherits its event subscribing capability from Subscribable:

var Person = function(name) {
	this.subscribers = {};
	this.name = name;
};

Person.prototype = new Subscribable();
Person.prototype.sayName = function() {
	console.log('Hi! I\'m ' + this.name + '.');
};

var Daniel = new Person('Daniel');

Daniel.sayName();
//=> Hi! I'm Daniel.

Daniel.on('smile', function showTeeth(event, numTeeth) {
	console.log('Oh look! ' + this.name + ' has ' + numTeeth + ' teeth.');
});

Daniel.trigger('smile', 30);
//=> Oh look! Daniel has 30 teeth.

Methods

• Subscibe to events: .on(eventsStr, handlerFn, callNow)
  • if callNow is truthy, handlerFn is called right away.
  • eventsStr should be a space-seperated list of events, e.g. 'start stop'. if eventsStr is 'any', then handlerFn will be called when any event is triggered on this instance of Subscribable, otherwise it will be called whenever an event in eventsStr is triggered.
• Trigger events: .trigger(eventStr[, value1[, ...[, valueN]]])
  • trigger the eventStr event. Any subscribing handlers will be called with the same arguments passed to .trigger().
• Unsubscribe from events: .off(eventsStr, handlerFn)
  • pass no arguments to cancel all subscriptions
  • pass eventsStr (a space-separated list of events) to unsubscribe all functions from those events
  • or pass eventsStr and a function to unsubscribe a specific function from those events

Extend

Add your own methods to the Subscribable prototype:

// subscribe, then unsubscribe after first trigger
Subscribable.prototype.once = function(event, fn) {
	var t = this;
	this.on(event, function() {
		fn.apply(this, arguments);
		t.off(event, fn);
	});
};