compute_helper

controllers.application.js

import Ember from 'ember';
import { A } from '@ember/array';
import EmberObject, { computed } from '@ember/object';
const { alias } = computed;

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  title: '',
  todos: null,
  currentItem: null,
  init() {
    this.set('todos', A([
      EmberObject.create({ title: 'Something' })
    ]));
    this.set('currentItem', this.todos[0]);
  },
    
  actions: {
    save() {
			this.set('currentItem.title', this.title);
    },
    
     getTitle(item) {
       console.log(item);
      return item.title;
    }
  }  
});

templates.application.hbs

<h1>Try</h1>
{{input value=title}}
<button onclick={{action 'save'}}>Save</button>
{{#each todos as |f|}}
<h1>{{f.title}} === {{compute (action 'getTitle') f}}</h1>

{{/each}}

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2",
    "ember-composable-helpers": "2.1.0"
  }
}