test

components.rd-block.component.js

import Ember from 'ember';

export default Ember.Component.extend({
  componentName: 'rd-block',
  mods: null,
  classNameBindings: ['componentName', 'modClassNames'],
  modClassNames: Ember.computed('componentName', 'mods', 'mods.[]', {
    get() {
      let componentName = this.get('componentName');
      let mods = this.get('mods') || [];
      return mods.map(function(mod) {
        return `${componentName}--${mod}`;
      }).join(' ');
    }
  }),
  init() {
    this._super(...arguments);
    this.set('mods', ['bgc-red']);
  },
  actions: {
    hit() {
      this.set('mods.hitted', true);
      //this.set('mod-hitted', true);
    }
  }
});

components.rd-block.template.hbs

<div
  class={{bem
    block=componentName
    element='header'
    mods='bgc-red opacity-06'
  }}
>
  test btn
</div>
<div
  class={{bem
    block=componentName
    element='elem'
  }}
></div>
<div
  class={{bem
    block=componentName
    element='footer'
    mods='bgc-blue opacity-06 test-1'
  }}
>
  <div
    class={{bem
      block='footer'
      mods='bgc-blue font-small'
    }}
  >
    123
  </div>
  qweqweqe
</div>

controllers.application.js

import Ember from 'ember';

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

helpers.bem.js

import Ember from 'ember';

export function bem(params, hash) {
  let block = Ember.get(hash, 'block') || '',
      element = Ember.get(hash, 'element') || '',
      mods = (Ember.get(hash, 'mods') || '').w();
  let classNameBasePart = element === '' ? `${block}` : `${block}__${element}`;
  return [
    classNameBasePart
  ].concat(
    mods.map(function(mod) {
      return `${classNameBasePart}--${mod}`;
    })
  ).join(' ');
}

export default Ember.Helper.helper(bem);

styles.app.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}
.rd-block {
  width: 100px;
  height: 100px;
  padding-right: 50px;
  background-color: #ccc;
}
.rd-block:hover {
  background-color: #aaa;
}
.rd-block--bgc-red,
.rd-block__header--bgc-red,
.rd-block__footer--bgc-red {
  background-color: #f00;
}
.rd-block--bgc-blue,
.rd-block__header--bgc-blue,
.rd-block__footer--bgc-blue {
  background-color: #00f;
}
.rd-block--overflow-auto,
.rd-block__header--overflow-auto,
.rd-block__footer--overflow-auto {
  overflow: auto;
}
.rd-block__elem {
  width: 100%;
  height: 20px;
  background-color: #008000;
}
.rd-block__header {
  width: 100%;
  height: 50px;
}
.rd-block__header--opacity-06 {
  opacity: 0.6;
}
.rd-block__header--test-1,
.rd-block__body--test-1,
.rd-block__footer--test-1 {
  padding: 4px;
  box-sizing: border-box;
  color: #fff;
  outline: 1px solid #f00;
}
.rd-block__body {
  width: 100%;
  height: calc(100% - 50px - 30px);
}
.rd-block__footer {
  width: 100%;
  height: 30px;
}
.footer--font-small {
  font-size: 8px;
}

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>
See <a href="http://codepen.io/Shacko/pen/KNYqqX">more</a>
<br>
<br>

{{rd-block}}

{{!- {{rd-block mods=(concat 'color' color ' ' isVisible)}}
{{!-
{{rd-block
  isVisible=isVisible
  type="text"
  mods=(hash 
    color=color
    isVisible=isVisible
  )
}}

{{!-
{{rd-block color_mod=color visible_mod=isVisible)}}

{{!-
{{rd-block
  isVisible=isVisible
  type="text"
	mod-color='red'
  mod-transparant='50'
}}

{{!-
rd-block--color-red {}
rd-block--transparant-50 {}
-}}

twiddle.json

{
  "version": "0.10.7",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.10.0",
    "ember-data": "2.10.0",
    "ember-template-compiler": "2.10.0",
    "ember-testing": "2.10.0"
  },
  "addons": {}
}