Marionette CompositeView Sort Rendering - backbone.js

Question

I have a Marionette (2.4.1) CompositeView and when I do a sort it re-renders the entire view rather than the childView. The header icons revert back. I could fix them on render but is there a way that I can just render the childView?
diaryEntries = Backbone.Marionette.CompositeView.extend({
template : diaryEntries,
className: 'diary-entries',
collection: new Diary(),
childViewContainer: 'tbody',
reorderOnSort: true,
events: {
'click th[data-sort]': 'sort',
'click .pagination a': 'paginate'
},
initialize: function() {
this.itemsPerPage = 5;
this.currentPage = 1;
this.pages;
},
...
sort: function(e) {
var $th, dir, sort, sorted;
e.preventDefault();
$th = $(e.currentTarget);
sort = $th.data('sort');
if (sort === this.collection.sortField) {
this.collection.sortDirection *= -1;
} else {
this.collection.sortDirection = 1;
}
this.collection.sortField = sort;
$('span.glyphicon').removeClass('active-sort');
$th.siblings('th').find('span.glyphicon').removeClass('glyphicon-chevron-down glyphicon-chevron-up').addClass('glyphicon-sort');
if (this.collection.sortDirection === 1) {
$th.find('span.glyphicon').removeClass('glyphicon-chevron-down glyphicon-sort').addClass('glyphicon-chevron-up active-sort');
} else {
$th.find('span.glyphicon').removeClass('glyphicon-chevron-up glyphicon-sort').addClass('glyphicon-chevron-down active-sort');
}
this.collection.sort();
},
...
});

Answer 1

Well, looks like Marionette was concerned about the same thing you are. I couldn't find this in the docs, but it's pretty plain in the source. If you pass this option:
reorderOnSort: true
into your Collection/Composite view, on a 'sort' event the Collection/View will not re render, just its children.
See this line in the Marionette source: https://github.com/marionettejs/backbone.marionette/blob/v2.4.1/src/collection-view.js#L166
UPDATE If you're filtering your children views, running sort on your collection will invoke render on the Collection/CompositeView. The logic is that if you're paginating your children results, then you must sort the original, unfiltered, collection to properly display paginated results.
Nonetheless, I don't see anything intrinsically wrong with paginating a filtered set.
Fortunately, its easy to override the sort method to render whether your results are filtered or not. On you Collection/CompositeView include this method:
reorder: function() {
var children = this.children;
var models = this._filteredSortedModels();
// get the DOM nodes in the same order as the models
var els = _.map(models, function(model) {
return children.findByModel(model).el;
});
this.triggerMethod('before:reorder');
this._appendReorderedChildren(els);
this.triggerMethod('reorder');
}
},