prefix/suffix

controllers.application.js

import Ember from 'ember';
import { computed } from '@ember/object';

const base = 'thisisabase'

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  original: 'prefix_thisisabase_suffix',
  
  prefix: computed({
    get() {
      return this.get('original').split(base)[0]; 
    }
  }),
  
  suffix: computed({
    get() {
     	return this.get('original').split(base)[1]; 
    }
  }),
  
  filename: computed('original', 'prefix', 'suffix', function() {
    return this.get('prefix') + base + this.get('suffix');
  })
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>

prefix: {{prefix}}
<br>
suffix: {{suffix}}
<br>

filename: {{filename}}

<br>
prefix:
<input value={{prefix}} oninput={{action (mut prefix) value="target.value"}}  />

<br>
suffix:
<input value={{suffix}} oninput={{action (mut suffix) value="target.value"}} />

twiddle.json

{
  "version": "0.15.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.2.2",
    "ember-template-compiler": "3.2.2",
    "ember-testing": "3.2.2"
  },
  "addons": {
    "ember-data": "3.2.0"
  }
}