Collapse/Expand

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',

  rows: [
  	1,
    2,
    3,
    4,
    5,
    6,
    7,
    8,
    9,
    10,
    11
  ],

  withShowMoreButton: Ember.computed('rows', function() {
    const tableRows = this.get('rows');
    const tableRowCount = tableRows.length;
    const maxRowsCollapsed = 10;

    if (tableRowCount <= maxRowsCollapsed) {
      return false;
    }
    
    return true;
  }),
  
  isExpanded: false,
  
  actions: {
  	toggleExpanded() {
    	this.toggleProperty('isExpanded');
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
<div class="{{if isExpanded "expanded"}}">
</div>
{{#if withShowMoreButton}}
	<button {{action "toggleExpanded"}}>Show More</button>
{{/if}}
<br>
<br>

twiddle.json

{
  "version": "0.10.5",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.8.0",
    "ember-data": "2.8.0",
    "ember-template-compiler": "2.8.0",
    "ember-testing": "2.8.0"
  },
  "addons": {}
}