JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://cloud.github.com/downloads/emberjs/ember.js/ember-latest.min.js"></script>
<script type='text/x-handlebars' data-template-name='item'><span>
    {{#with content}}
        {{name}}
    {{/with}}
    </span></script>

<div id="main"></div>

JavaScript

App = Ember.Application.create({});

App.Item = Ember.View.extend({
    templateName: "item",
    didInsertElement: function() {
        console.log('just inserted ' + this.getPath('content.name'));
    }
});

App.CollectionView = Ember.CollectionView.extend({
    itemViewClass: "App.Item",
    contentBinding: "App.collectionController",
    
    willInsertElement: function() {
        // The CollectionView should be in the "hasElement" state... which is pre-rendering.  
        console.log(this.get('state'));
    },
    didInsertElement: function() {
        // The CollectionView and all of it's children should be rendered now and it should be in the "inDOM" state... which is post rendering.
        console.log(this.get('state'));
        
        $.each(this.$('span'), function(index, value) { 
            $(value).after($(value).offset().top) 
        });
            
        // A run loop is started for a view when it's initialized and
        // is ended when it's initialization is completed.
        // That processes includes rendering all of this view's children.
        // And after all of its childrens didInsertElemnt calls are made.
        
        // Hopefully this is the hook you're looking for.
        Ember.run.once(this, function() {
            console.log('inside run.once');
        });
    }
});

App.collectionController = Ember.ArrayController.create({
    content: []
});

var collectionView = App.CollectionView.create();
collectionView.appendTo("#main")
    
App.collectionController.addObject({
    name: "Thing"
});

App.collectionController.addObject({
    name: "Other Thing"
});