region-extras add block helper support

regionHelper.js

// ...
if (options.fn) {
  var View = LayoutView.extend({
    template: () => options.fn(hash.defaults)
  });
  region.show(new View());
  region.render = function (data) {
    var View = LayoutView.extend({
      template: () => options.fn(extend(hash.defaults, data))
    });
    this.show(new View());
  }
}

View.hbs

{{#region "buttonState" defaults=(obj disabled=false) }}
    {{button
    	disabled=disabled 
    }}
{{/region}}

{{#region "buttonState2" defaults=(obj disabled=false) }}
    {{view "../1"
    	disabled=disabled 
    }}
    {{view "../1"
    	disabled=disabled 
    }}
{{/region}}

View.js

class View extend LayoutView {
	
	template: require('./View.hbs'),
	
	collectionEvents: {
		'request': 'enableButton',
		'sync error': 'disableButton'
	}

	enableButton() {
		/** 
		 * region.render(data) will call Handlebars' options.fn(data))
		 */
		this.getRegion('buttonState').render({disabled: false});
	}

	disableButton() {
		this.getRegion('buttonState').render({disabled: true});
	}

}