patlama#2

components.to-update-fields.js

import Ember from 'ember';
const {computed} = Ember;

let Errors = Ember.Object.extend({  
  /*
  errorsX: computed.alias('component.errors.x'),
  errorsY: computed.alias('component.errors.y'),
  errorsZ: computed.alias('component.errors.external'),
  */
  errorsXBinding: 'component.errors.x',
  errorsYBinding: 'component.errors.y',
  errorsZBinding: 'component.errors.z'
});

export default Ember.Component.extend({
  init() {
    this._super(...arguments);
    this.set('errorBag', Errors.create({component:this}));
  },
  
  errors:Ember.computed('item.x','item.y', 'externalField', function(){
    return Ember.merge({'x': this.get('item.x'), 'y': this.get('item.y')}, 
                      this.get('externalField'));
  }),
  
  actions: {
    onupdateX(value) {
      this.get('item').set('x', value);
    },
    
    onupdateY(value) {
      this.get('item').set('y', value);
    },
    
    onexternalupdate(value) {
      this.set('externalField', value);
    }
  }
});

components.to-update-subfield.js

import Ember from 'ember';

export default Ember.Component.extend({
  errors:Ember.computed('item.z', function(){
     let z = {'z': this.get('item.z')};
     this.get('onexternalupdate')(z); 
     return z;
  }),
 
    actions: {
      onupdateZ(value) {
        this.get('item').set('z', value);
      },
    }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  item: Ember.Object.create({})
});

templates.application.hbs

{{to-update-fields item=item}}

<br>

templates.components.to-update-fields.hbs

<b>To update field</b>
<br>
{{errorBag.errorsX}}-{{errorBag.errorsY}}-{{errorBag.errorsZ}}
<br>
<input value={{item.x}} oninput={{action 'onupdateX' value="target.value"}}>
<input value={{item.y}} oninput={{action 'onupdateY' value="target.value" }}>
<br><br>
{{to-update-subfield item=item onexternalupdate=(action 'onexternalupdate')}}

templates.components.to-update-subfield.hbs

<input value={{item.z}} oninput={{action 'onupdateZ' value="target.value"}}>
{{errors.z}}

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": {
    "ember-data": "2.12.1"
  }
}