computeds that get keys not depended on

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  
  notDependedOn: '',
  
  dependedOn: '',
 
  someResult: Ember.computed('dependedOn', function() {
    return this.get('dependedOn') + ' ' +
           this.get('notDependedOn'); 
  }), 
  
  actions: {
    set: function(target) {
      const key = target.dataset.key;
      debugger;
      this.set(key, target.value);
    }
  }
  
});

templates.application.hbs

<input placeholder="name"
       value={{name}}
       onchange={{action "set" value="target"
       data-key="dependedOn"}}/>
<input placeholder="lastname"
       value={{lastname}}
       onchange={{action "set" value="target"
       data-key="notDependedOn"}}/>

<p>
  result: {{someResult}}
</p>

twiddle.json

{
  "version": "0.12.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.12.0",
    "ember-template-compiler": "2.12.0",
    "ember-testing": "2.12.0"
  },
  "addons": {
  }
}