Track Inner

controllers.application\.js

import Controller from '@ember/controller';
import { tracked } from '@glimmer/tracking';
import { action } from '@ember/object';

class Item {
  @tracked count;
  constructor(content, count) {
    this.content = content;
    this.count = count;
  }
}

export default class ApplicationController extends Controller {
   @tracked markedValues = {
      item1: new Item("This is item1", 1),
      item2: new Item("This is item2", 1)
   }

   @action updateCount(itemKey) {
       this.markedValues[itemKey].count = this.markedValues[itemKey].count + 1;
       this.markedValues = {...this.markedValues}
   }
}

templates.application\.hbs

{{#each-in this.markedValues as |key value|}}
        <div {{on "click" (fn this.updateCount key)}}>{{value.content}} and number is {{value.count}}</div>
  {{/each-in}}

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
    "ember": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}