Simple event triggering/handling framework

event-framework.js

function hasProperty(obj, prop) {
    return obj[prop] !== undefined;
};

Array.prototype.callFunction = function(target, key) {
    var args = [].splice.call(arguments, 0).slice(2);

    this.forEach(function(elem) {
        try {
            if (hasProperty(elem, key) && typeof elem[key] == 'function') {
                elem[key].apply(target, args);
            } else if (!key && typeof elem == 'function') {
                elem.apply(target, args);
            }
        }
        catch(e) {}
    });
};

obj.on = function(key, handler) {
    this.eventListeners = (this.eventListeners || {});
    this.eventListeners[key] = (this.eventListeners[key]||[]);
    this.eventListeners[key].push(handler);
    return this;
}

obj.trigger = function(key, data) {
    this.eventListeners = (this.eventListeners || {});
    var listeners = (this.eventListeners[key] || []);

    listeners.callFunction(this, '', data);
    return this;
}

obj.off = function(key) {
    this.eventListeners[key] = [];
    return this;
};

example.js

obj.on('example-event', function(data) {
    console.log('received example-event with data: ' + JSON.stringify(data))
});

obj.trigger('example-event', {
    // Data is here
    exampleData: 2,
    moreData: 3
})