GTK+ widget templates now in Javascript

Let's get the features in early!

If you're working on a Javascript application for GNOME, you'll be interested to know that you can now write GTK+ widget templates in gjs.

Many thanks to Giovanni for writing the original patches. And now to a small example:

const MyComplexGtkSubclass = new Lang.Class({
    Name: 'MyComplexGtkSubclass',
    Extends: Gtk.Grid,
    Template: 'resource:///org/gnome/myapp/widget.xml',
    Children: ['label-child'],

    _init: function(params) {
        this.parent(params);

        this._internalLabel = this.get_template_child(MyComplexGtkSubclass,
                                                      'label-child');
    }   
});

And now you just need to create your widget:

let content = new MyComplexGtkSubclass();
content._internalLabel.set_label("My updated label");

You'll need gjs from git master to use this feature. And if you see anything that breaks, don't hesitate to file a bug against gjs in the GNOME Bugzilla.