Delegating events to a parent view in Backbone

Question

My view, TuneBook, has several child views of type ClosedTune. I also have separate full page views for each tune, OpenTune. The same events are bound within ClosedTune and OpenTune, so I've designed my app so that they both inherit from a shared 'abstract' view Tune.

To make my app more scaleable I would like the events for each ClosedTune to be delegated to TuneBook, but for maintainability I would like the same handlers (the ones stored in Tune) to be used by TuneBook (although they'd obviously need to be wrapped in some function).

The problem I have is, within TuneBook, finding the correct ClosedTune to call the handler on. What's a good way to architect this, or are there other good solutions for delegating events to a parent view?

Note - not a duplicate of Backbone View: Inherit and extend events from parent (which is about children inheriting from a parent class, whereas I'm asking about children which are child nodes of the parent in the DOM)

Answer 1

In your parent view (extending also from Backbone.Events), I would bind onEvent to the DOM event. On trigger, it would fire a backbone event including some "id" attribute that your child views know (presumably some row id?).

var TuneBook = Backbone.View.extend(_.extend({}, Backbone.Events, {
    events: {
        "click .tune .button": "clickHandler"
    },
    clickHandler: function (ev) {
        this.trigger('buttonClick:' + ev.some_id_attr, ev);
    },

}));

Child views would then naturally subscribe to the parent views event that concerns them. Below I do it in initialize passing the parent view as well as that special id attribute you used before in options.

var ClosedTune = Backbone.View.extend({

    initialize: function (options) {
        options.parent.on('buttonClick:' + options.id, this.handler, this);
    },

    handler: function (ev) {
        ...
    },

});

You can of course also set up similar subscribers on Tune or OpenTune.