render

components.my-component-child.js

import Ember from 'ember';

export default Ember.Component.extend({
  willRender() {
     console.log('child will A');
    this._super(...arguments);
     console.log('child will B');
    //
    //alert('my-component-child willRender');
  },
  didRender() {
     console.log('child did A');
    this._super(...arguments);
     console.log('child did B');
   // alert('my-component-child didRender');    
  },
	name: null,
  actions: {
  	  updateName() {
        this.set('name', Math.random());
      }
  }
});

components.my-component-parent.js

import Ember from 'ember';

export default Ember.Component.extend({
  willRender() {
    console.log('parent will A');
    this._super(...arguments);
     console.log('parent will B');
    //alert('my-component-parent willRender');
  },
  didRender() {
     console.log('parent did A');
    this._super(...arguments);
     console.log('parent did B');
		//a//lert('my-component-parent didRender');
  },
  
  actions: {
      updateName() {
       this.set('name', Math.random()); 
      }
  }
});

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  willRender() {
    console.log('my will A')
    this._super(...arguments);
    console.log('my will B')
   // alert('my-component willRender');
  },
  didRender() {
    console.log('my did A')
    this._super(...arguments);
    console.log('my did B')
		//alert('my-component didRender');
  },
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  actions: {
    updateRandom() {
      this.set('random', Math.random());
    }
  }
});

templates.application.hbs

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

<button {{action 'updateRandom'}}>update</button>

{{my-component-parent random=random}}

{{outlet}}
<br>
<br>

templates.components.my-component-child.hbs

my-component-child {{random}} {{name}} <button {{action 'updateName'}}>update child</button>
{{yield}}

templates.components.my-component-parent.hbs

my-component-parent {{random}} {{name}} <button {{action 'updateName'}}>update parent</button>
{{my-component random=random}}

templates.components.my-component.hbs

my-component {{random}}
{{my-component-child random=random}}

twiddle.json

{
  "version": "0.12.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.12.0",
    "ember-template-compiler": "2.12.0",
    "ember-testing": "2.12.0"
  },
  "addons": {
    "ember-data": "2.12.1"
  }
}