Template as data

components.my-list.item.js

import Ember from 'ember';
import { next } from '@ember/runloop';

export default Ember.Component.extend({
  
  init() {
    this._super(...arguments);
    
    next(() => {
      this.list.items.pushObject(this);
    });
  }
  
});

components.my-list.js

import Ember from 'ember';
import { next } from '@ember/runloop';

export default Ember.Component.extend({
  
  init() {
    this._super(...arguments);
    
    this.set('items', []);
  }
  
});

templates.application.hbs

<MyList as |List|>
  <List.item>
    Item 1
  </List.item>
  <List.item>
    Item 2
  </List.item>
</MyList>

<MyList as |List|>
  {{#each (array 'a' 'b' 'c' 'd') as |value|}}
  	<List.item>
    	Item {{value}}
  	</List.item>
  {{/each}}
</MyList>

templates.components.my-list.hbs

<p>I'm a list with {{items.length}} items.</p>

{{yield (hash
	item=(component 'my-list/item'
    list=this
  )
)}}

templates.components.my-list.item.hbs

{{yield}}

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",
    "ember-array-helper": "4.0.0"
  }
}