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Latest commit 6095fb6 Sep 18, 2018


R. Sparkles

Addon used to experiment with @glimmer/component style APIs in Ember apps via existing public APIs.


ember install sparkles-component


The sparkles-component API supports most of the @glimmer/component API, including:

  • Lifecycle hooks
    • constructor - will be called when the component is needed, passed the evaluated named arguments for the component
    • didInsertElement - will be called after the component has been rendered the first time, after the whole top-down rendering process is completed
    • didUpdate - will be called after the component has been updated, after the whole top-down rendering process is completed
    • destroy - will be called when the component is no longer needed
  • Tracked properties
    • Support for setting local properties (triggering a rerender of that property)
    • Support for setting up dependent keys to cause a properties getter to be invoked again
    • Support for tracking class fields
  • Decorator Support
    • Support for consuming with Babel 6 (just install @ember-decorators/babel-transform)
    • Support consuming via TypeScript (enable via experimentalDecorators compiler option in tsconfig.json)

Missing features from @glimmer/component:

  • Access to this.bounds within the component. At the moment there is no access available at all to the rendered DOM. The easiest work around for now would be to use an attribute in your template along with document.querySelector.
  • Access to this.debugName within the component. This was largely only present for debugging purposes, but is not possible to access in the Ember APIs at the moment.


Comprehensive example (nearly exactly the same as the the glimmer.js guides):

// app/components/conference-speakers.js (.ts would also work)
import Component, { tracked } from "sparkles-component";

export default class ConferenceSpeakers extends Component {
  @tracked current = 0;
  speakers = ['Tom', 'Yehuda', 'Ed'];

  get currentlySpeaking() {
    return this.speakers[this.current];

  get moreSpeakers() {
    return (this.speakers.length - 1) > this.current;

  next() {
    this.current = this.current + 1;
{{!-- app/templates/components/conference-speakers.hbs --}}

  <p>Speaking: {{currentlySpeaking}}</p>
    {{#each speakers key="@index" as |speaker|}}

  {{#if moreSpeakers}}
    <button onclick={{action next}}>Next</button>
    <p>All finished!</p>



  • git clone <repository-url>
  • cd sparkles-component
  • yarn install


  • yarn lint:js
  • yarn lint:js --fix

Running tests

  • ember test – Runs the test suite on the current Ember version
  • ember test --server – Runs the test suite in "watch mode"
  • ember try:each – Runs the test suite against multiple Ember versions

Running the dummy application

For more information on using ember-cli, visit


This project is licensed under the MIT License.