backbone.vdomview

Note: Check out Skeletor instead

If you're looking for a way to write declarative views that only update the changed parts of the DOM, take a look at Skeletor, and in particular the ElementView class.

It does the same thing as the VDOMView in this package, but much better and quicker.

Skeletor is a fork of Backbone that adds various new features, but you can continue using Backbone and just start using the ElementView.

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This library provides a VirtualDOM-aware Backbone View, called Backbone.VDOMView.

It depends on snabbdom for the virtual-DOM implementation.

How to use

To use it, extend Backbone.VDOMView. Then, instead of implementing a render method in your view, add a toHTML method which returns the View's HTML as a string (or alternatively, add a toDOM method which returns a single DOM element).

The HTML of the toHTML must be structured so that there's a root element containing everything else. This root element is the view's top-level element, in other words, it's the DOM node represented by the this.el or this.$el attribute of the View.

React has a similar requirement that JSX returned by a component's render method should have a root node which contains everything else.

The rest will then be handled by VDOMView, which will automatically generate a diff between the view's current DOM element and new virtual-DOM node and then patch the actual DOM with this diff.

For example:

const MyView = Backbone.VDOMView.extend({

    tagName: 'span',
    className: 'vdom-span',

    toHTML () {
        return this.template(_.assign(this.model.toJSON()));
    }
});

The toHTML method

One important difference between Backbone.VDOMView and Backbone.View that should be noted is that the HTML being rendered (in the case of Backbone.VDOMView this is done in the toHTML method) should include the root element of the view.

So in the example above toHTML should return <span class="vdom-span"> ... </span> as the outer part of the HTML string.

This is different from normal Backbone.View classes, where your template will only return the inner part of the view element.

Event registration on virtual nodes

Snabbdom implements non-core functionality in separate modules.

Backbone.VDOMView makes use of all Snabbdom's modules except for the eventlisteners module.

The eventlisteners module allows you to add event listeners when creating a virtual node via the h method.

However Backbone.VDOMView doesn't use the h method of Snabbdom at all (it doesn't even include the code for it). Instead, it expects you to render the HTML for the view in the toHTML method, for example by using an underscore or lodash template.

There's therefore no way to attach these event listeners.

This way of registering event listeners is also in contrast to Backbone's declarative way of registering events, which is more the "Backbone way".

Backbone.VDOMView will make sure that these declaratively registered event listeners will remain active whenever the View's DOM representation changes.

The beforeRender and afterRender lifecycle methods

Backbone.VDOMView will call two lifecycle methods (if they exist). These are beforeRender and afterRender and are respectively called before and after toHTML is called.

Using Backbone.VDOMView without jQuery

Backbone can be used without jQuery by using Backbone.NativeView instead of Backbone.View.

If Backbone.NativeView is available, then the VDOMView will use that instead of Backbone.View.

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Backbone.VDOMView is used in converse.js.

If you have any questions, feel free to create an issue or contact me directly.