Increase font size

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName:'For Igor Storozhuk'
});

application.template.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{#change-font-size as |fontSize|}}
	{{example-text fontSize=fontSize}}
{{/change-font-size}}

<br>
<br>

change-font-size.component.js

import Ember from 'ember';

export default Ember.Component.extend({
  fontSize: 14,
  
  actions: {
    increaseFontSize() {
      let newFontSize = this.get('fontSize') + 1;
      return this.set('fontSize', newFontSize);
    },
    
    decreaseFontSize() {
      return this.set('fontSize', this.get('fontSize') - 1);
    }
  }
});

change-font-size.template.hbs

<button {{action 'increaseFontSize'}}> + </button>
<button {{action 'decreaseFontSize'}}> - </button>

{{yield fontSize}}

example-text.component.js

import Ember from 'ember';

export default Ember.Component.extend({
  
  fontSize: 16,
  
  displayFontSize: Ember.computed('fontSize', function(){
    let newFontSize = parseInt(this.get('fontSize'), 10);
    return new Ember.Handlebars.SafeString(`font-size: ${newFontSize}px`);
  }),
  
  h3FontSize: Ember.computed('fontSize', function(){
    let newFontSize = parseInt(this.get('fontSize') * 1.5, 10);
    return new Ember.Handlebars.SafeString(`font-size: ${newFontSize}px`);
  })
 });

example-text.template.hbs

<h3 style={{h3FontSize}}>The Title</h3>
<p class="special-text" style={{displayFontSize}}>some text.</p>

styles.app.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}

twiddle.json

{
  "version": "0.4.16",
  "EmberENV": {
    "FEATURES": {}
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.1.0/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/2.1.0/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.1.0/ember-template-compiler.js"
  }
}