Namespace: evento

Classes

EventTarget

Methods

<static> off(element, type, listener, auxArg)

Removes added listener matching the element/type/listener/auxArg combination exactly. If this combination is not found there are no errors.

var o = {handleEvent:function(){}, handleClick:function(){}};
evento.off(document.body, 'click', o);
evento.off(document.body, 'click', o, 'handleClick');
evento.off(document.body, 'click', o, fn);
evento.off(document.body, 'click', fn);
evento.off(document.body, 'click', this.handleClick, this);

Parameters:

Name	Type	Argument	Description
element	EventTarget		The object you'd like to stop observing.
type	string		The name of the event.
listener	Object | function		The listener object or callback function.
auxArg	string | Object	<optional>	See description.

Source:

• maria.js, line 287

<static> on(element, type, listener, auxArg)

If the listener is an object then when a matching event type is dispatched on the event target, the listener object's handleEvent method will be called. By supplying a string value for auxArg, you can specify the name of the method to be called. You can also supply a function object for auxArg for early binding.

If the listener is a function then when a matching event type is dispatched on the event target, the listener function is called with event target object set as the this object. Using the auxArg, you can specifiy a different object to be the this object.

One listener (or type/listener/auxArg pair to be more precise) can be added only once.

var o = {
    handleEvent: function(){},
    handleClick: function(){}
};

// late binding. handleEvent is found when each event is dispatched
evento.on(document.body, 'click', o);

// late binding. handleClick is found when each event is dispatched
evento.on(document.body, 'click', o, 'handleClick');

// early binding. The supplied function is bound now
evento.on(document.body, 'click', o, o.handleClick);
evento.on(document.body, 'click', o, function(){});

// supplied function will be called with document.body as this object
evento.on(document.body, 'click', function(){});

// The following form is supported but is not neccessary given the options
// above and it is recommended you avoid it.
evento.on(document.body, 'click', this.handleClick, this);

Parameters:

Name	Type	Argument	Description
element	EventTarget		The object you'd like to observe.
type	string		The name of the event.
listener	Object | function		The listener object or callback function.
auxArg	string | Object	<optional>	See description.

Source:

• maria.js, line 285

<static> purge(listener)

Removes all registrations of the listener added through evento.on. This purging should be done before your application code looses its last reference to listener. (This can also be done with more work using evento.off for each registeration.) If the listeners are not removed or purged, the listener will continue to observe the EventTarget and cannot be garbage collected. In an MVC application this can lead to "zombie views" if the model data cannot be garbage collected. Event listeners need to be removed from event targets in browsers with circular reference memory leak problems (i.e. old versions of Internet Explorer.)

The primary motivation for this purge function is to ease cleanup in MVC View destroy methods. For example,

var APP_BoxView = function(model, controller) {
    this.model = model || new APP_BoxModel();
    this.controller = controller || new APP_BoxController();
    this.rootEl = document.createElement('div');

    // subscribe to DOM node(s) and model object(s) or anything else
    // implementing the EventTarget interface using listener objects
    // and specifying method name using the same subscription interface.
    //
    evento.on(this.rootEl, 'click', this, 'handleClick');
    evento.on(this.model, 'change', this, 'handleModelChange');
};

APP_BoxView.prototype.handleClick = function() {
    // might subscribe/unsubscribe to more DOM nodes or models here
};

APP_BoxView.prototype.handleModelChange = function() {
    // might subscribe/unsubscribe to more DOM nodes or models here
};

APP_BoxView.prototype.destroy = function() {

    // Programmer doesn't need to remember anything. Purge all subscriptions
    // to DOM nodes, model objects, or anything else implementing
    // the EventTarget interface in one fell swoop.
    //
    evento.purge(this);
};

Parameters:

Name	Type	Description
listener	EventListener	The listener object that should stop listening.

Source:

• maria.js, line 289