Ember readsWithDefault CP

components.drop-down.js

import Ember from 'ember';

const {
  getWithDefault,
  computed
} = Ember;

function readsWithDefault(dependentKey, defaultValue) {
  return computed(dependentKey, {
    get() {
      return getWithDefault(this, dependentKey, defaultValue);
    },
    set(key, value) {
      return value;
    }
  });
}

export default Ember.Component.extend({
  open: readsWithDefault('isOpen', false),
  
  actions: {
    toggleDropDown() {
      this.toggleProperty('open');
    }
  }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  isOpen: false,
  
  actions: {
    toggleDropDown() {
      this.toggleProperty('isOpen');
    }
  }
});

templates.application.hbs

<h1>DDAU for public properties with common behaviour
Raw
</h1>
<br>
<span {{action 'toggleDropDown'}}>Toggle Controller</span>: {{isOpen}}

{{drop-down isOpen=isOpen}}

templates.components.drop-down.hbs

<span {{action 'toggleDropDown'}}>Toggle Component</span>: {{open}}

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": {}
}