yield

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName:'Ember Twiddle'
});

application.route.js

import Ember from 'ember';

export default Ember.Route.extend({
  model() {
  	return [ {foo: 'bar'} ]
  }
});

application.template.hbs

<h1>Welcome to {{appName}}</h1>

{{#prepare-data 
	data=model 
  offset=offset
  perPage=perPage
  as |prepared actions|
}}
	{{#each prepared as |item|}}
  	{{item.name}} <button {{action actions.toggleLeaf item}}>Open</button>
  {{/each}}
{{/prepare-data}}

prepare-data.component.js

import Ember from 'ember';

export default Ember.Component.extend({
  // data: [],
  // _data: [],
  didReceiveAttrs() {
    this._super(...arguments);
    
    let isOffsetChanged = this.get('offset') !== this.get('_offset');
    if (isOffsetChanged) {
    	let data = this.get('_data');
      fetchFromStore().then(function(newData){
        data.pushObjects(newData);
      });
    }
    
    this.set('_offset', this.get('offset'));
  },
  actions: {
  	toggleLeaf(item) {
    	//
    }
  }
});

prepare-data.template.hbs

{{yield _data (hash 
	toggleLeaf=(action 'toggleLeaf')
)}}

twiddle.json

{
  "version": "0.5.3",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.3.1/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/2.3.3/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.2.0/ember-template-compiler.js"
  }
}