New Twiddle

components.my-component\.js

import Component from '@glimmer/component';
import { tracked } from '@glimmer/tracking';
import { action } from '@ember/object';

let index = 0;

export default class extends Component {
  @tracked obj = {
  	index: 0
  };
  
  get edges() {
    return Object.keys(this.obj).map(key => {
      return {
        d: this.obj[key]
      };
    })
  }
  
  @action
  update() {
    this.obj = {
      index: ++index
    };
  }
}

controllers.application\.js

import Controller from '@ember/controller';

export default class ApplicationController extends Controller {
  appName = 'Ember Twiddle';
}

templates.application\.hbs

<h1>Welcome to {{this.appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>
<MyComponent/>

templates.components.my-component\.hbs

{{yield}}
<button {{on 'click' this.update}}>Update</button>

{{#if this.edges}}
            <svg
              viewBox="0 0 400 400"
              style="width: 400px; height: 400px"
              stroke="#000"
              fill="#000"
              strokeWidth="3"
            >
              {{#each this.edges as |edge|}}
                <path d="M150 {{edge.d}} L75 200 L225 200 Z" />
              {{/each}}
            </svg>
          {{/if}}

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"
  }
}