Child components

components.child-machine\.js

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

export default class extends Component {
  get context() {
    return JSON.stringify(this.args.machine.machine.context)
  }
  
  @action
  updateContext() {
    this.args.machine
      .onTransition((state) => console.log('CHILD STATE: ', state))
      .send("UPDATE_CONTEXT")
  }
}

components.parent-machine\.js

import Component from '@glimmer/component';
import { matchesState, useMachine } from 'ember-statecharts';
import { createMachine, send, assign, spawn } from 'xstate'
import { action } from '@ember/object'
import { use } from 'ember-usable';

const counterMachine = createMachine({
  id: 'timer',
  initial: 'active',
  context: {
    count: 0,
  },
  states: {
    active: {
      entry: [send('INC', { delay: 1000 })],
      on: {
        INC: {
          target: 'active',
          actions: [
            assign({
              count: (context) => context.count + 1,
            }),
          ],
        },
      },
    },
  },
});

const parentMachine = createMachine({
  id: 'parent',
  initial: 'active',
  context: {
    counterRef: null,
  },
  states: {
    active: {
      entry: [
        assign({
          counterRef: () => spawn(counterMachine, { sync: true }),
        }),
      ],
    },
  },
});



export default class extends Component {
  @use statechart = useMachine(parentMachine).onTransition((state) => console.log("PARENT STATE: ", state));

  get parentCount() {
    const counterRef = this.statechart.state.context.counterRef;
    
    if (counterRef) {
      return counterRef.state.context.count;
    } else {
      return 0;
    }
  }

}

controllers.application\.js

import Controller from '@ember/controller';

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

templates.application\.hbs

<ParentMachine />

<br>
<br>

templates.components.child-machine\.hbs

<h2>CHILD MACHINE</h2>

<div>
	{{this.context}}
</div>

<button {{on "click" this.updateContext}}>UPDATE CONTEXT WITH NEW VALUE</button>

templates.components.parent-machine\.hbs

<h1>Parent Machine</h1>
<div>Child Count: {{this.parentCount}}</div>

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",
    "ember-statecharts": "0.13.2"
  }
}