Set values on a POJO

controllers.application.js

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

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  tempObj: computed(function() {
  	return {};
  }),
  
  actions: {
  	submit(key, value) {
      console.log('submit');
    	set(this.tempObj, key, value);
    }
  }
});

templates.application.hbs

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

<form {{action "submit" key value on="submit"}}>
	{{input value=key placeholder="key"}}
	{{input value=value placeholder="value"}}
  <button type="submit">Submit</button>
</form>

{{#each-in tempObj as | tempKey tempValue |}}
	{{tempKey}}: {{tempValue}} <br>
{{/each-in}}

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"
  }
}