Nice little TickEventEmitter (EventEmitter extension with automatic tick support)

README.md

Dependencies

• heir.js
• EventEmitter

TickEventEmitter.js

define(['lib/EventEmitter', 'lib/heir'], function(EventEmitter) {

    /**
     * This is an extended version of EventEmitter with "tick" events
     * built in. Extending this will also give you EventEmitter functionality.
     */
    var TickEventEmitter = function TickEventEmitter() {
    };

    TickEventEmitter.inherit(EventEmitter);

    /**
     * This sets up TickEventEmitter
     */
    TickEventEmitter.prototype.initTick = function() {

        this._initTick = true;

        /**
         * We'll create a binded version of the tick method,
         * to speed stuff up
         */
        this.tick = this.tick.bind(this);

        /**
         * Create a version of trigger that only triggers
         * the tick event, for setTimeout
         */
        this.trigger_tick = this.trigger.bind(this, 'tick');

        /**
         * Start the tick loop
         */
        this.tick();
    };

    /**
     * Have we initiated TickEventEmitter yet?
     * @type {Boolean}
     */
    TickEventEmitter.prototype._initTick = false;

    /**
     * We'll overwrite addListener, so we can "pretend" autoinit.
     */
    TickEventEmitter.prototype.addListener =
    TickEventEmitter.prototype.on          = function() {
        if (!this._initTick) {
            this.initTick();
        }

        return EventEmitter.prototype.addListener.apply(this, arguments);
    };

    /**
     * This variable controls the stopping of ticking.
     * Set this to false to stop the ticking
     * @type {Boolean}
     */
    TickEventEmitter.prototype.ticking = true;

    /**
     * This function is called for each tick.
     */
    TickEventEmitter.prototype.tick = function() {
        if (!this.ticking) {
            return;
        }

        setTimeout(this.trigger_tick);
        setTimeout(this.tick);
    };

    return TickEventEmitter;

});

usage.js

require(['TickEventEmitter'], function(TickEventEmitter) {
    var Thing = function(){
        this.started = Date.getTime();
        this.elapsed = 0;

        this.on('tick', this.updateElapsed);
    };

    Thing.inherit(TickEventEmitter);

    Thing.prototype.updateElapsed = function() {
        this.elapsed = Date.getTime() - this.started;

        if (this.elapsed % 60000 === 0) {
            this.trigger('minute');
        }

        if (this.elapsed % (60 * 60 * 1000) === 0) {
            this.trigger('hour');
        }

        // ... 
    };

    var thing = new Thing();

    thing.on('minute', function() {
        alert('Minute has passed!');
    });
});