style attribute helper

components.example-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  attributeBindings: ['style']
});

controllers.application.js

import Ember from 'ember';

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

helpers.style.js

import Helper from 'ember-helper';
import {htmlSafe} from 'ember-string';

export function style(params, hash) {
  return htmlSafe(JSON.stringify(hash)
                    .replace(/,/g, ';')
    						    .replace(/[{"}]/g, ''))
}

export default Helper.helper(style);

templates.application.hbs

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

<!-- static style, easy to understand-->
{{#example-component style="color: blue; font-size: 1em"}}
  TEST
{{/example-component}}

<!-- dynamic style but hard to read and write -->
{{#with (hash color="red" font-size="1.25em") as |s|}}
  {{#example-component
  	style=(concat "color:" s.color ";font-size:" s.font-size)}}
    TEST
  {{/example-component}}
{{/with}}

<!-- dynamic style with easy syntax by using helper -->
{{#with (hash color="green" font-size="2em") as |s|}}
	{{#example-component
  	style=(style color=s.color font-size=s.font-size)}}
  	TEST
	{{/example-component}}
{{/with}}

templates.components.example-component.hbs

{{yield}}

twiddle.json

{
  "version": "0.11.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "release",
    "ember-template-compiler": "release",
    "ember-testing": "release"
  },
  "addons": {}
}