change-in-array-and-rerender

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  clientList: null,
  dataItems: Ember.computed('clientList.@each.username', function(){
    return this.get('clientList');
  }),
  init(){
    this._super(...arguments);
    let array = [];
    for(let i = 0; i < 8; ++i){
      let obj = {};
      obj.id = i;
      obj.username = `user-${i}`;
      obj.computername = `computer-${i * i}`;
      array.pushObject(obj);
    }
    this.set('clientList', array);
  },
  actions: {
    change(){
      let i = Math.floor(Math.random() * 7);
      let item = this.get('clientList').objectAt(i);      
      Ember.set(item, 'id', Math.floor(Math.random() * 500));      
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
<table border=1>
<tr>
  <td>id</td>
  <td>username</td>
  <td>computername</td>  
</tr> 
{{#each dataItems as |client|}}
<tr>
  <td>{{client.id}}</td>
  <td>{{client.username}}</td>
  <td>{{client.computername}}</td>  
</tr>  
{{else}}
  Sorry, nobody is here.
{{/each}}
</table>
<br>
<button {{action 'change'}}>Change on item</button>
<br>

twiddle.json

{
  "version": "0.10.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.6.0",
    "ember-data": "2.6.1",
    "ember-template-compiler": "2.6.0"
  },
  "addons": {}
}