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HTML

              
                <button class="incButton">Increment</button>
<button class="decButton">Decrement</button>
<button class="decaIncButton">Increment by 10 in 3 seconds</button>

<my-counter></my-counter>
              
            
!

CSS

              
                
              
            
!

JS

              
                class ZeroFux {
  constructor(element) {
    if (element) {
      this.dispatcher = element;
    } else {
      this.dispatcher = document.querySelector('body');
    }
  }

  // The dipatch method takes an action argument
  // of the previously defined action type.
  dispatch(action) {
	  this.dispatcher.dispatchEvent(
		  new CustomEvent(action.type, {
		    detail: action,
		    // In case you set a custom dispatcher element
		    // and want them to bubble.
		    bubbles: true,
		    // In case your custom dispatcher is in the
		    // Shadow DOM and you want them to bubble between
		    // the borders or Shadow DOM and regular DOM.
		    compose: true,
		  })
		)
  }

  // This method takes an array of action types
  // that can influence a component's state,
  // an object with reducers with the same names
	// as the action types and a reference
	// to the component on which we want to set
	// the state propery.
  setReducers(actionTypes, reducers, component) {
		actionTypes.forEach(actionType => {
			if (reducers[actionType]) {
				this.dispatcher.addEventListener(actionType, e => {
					const action = e.detail;
					component.state = reducers[actionType](component.state, action);
				});
			} else {
				throw new Error(
					`Please add a reducer for the "${actionType}" action.`
				);
			}
		});
	}
}

const zeroFux = new ZeroFux();

const actionTypes = ['INCREMENT', 'DECREMENT', 'INCREMENT_X'];

const reducers = {
  'INCREMENT': (state, action) => parseInt(state) + 1,
  'DECREMENT': (state, action) => parseInt(state) - 1,
  'INCREMENT_X': (state, action) => parseInt(state) + action.payload,
}

// Update the counter with ZeroFux:
class Counter extends HTMLElement {
  constructor() {
    super();
    this.attachShadow({ mode: 'open' });
    this.state = 0;
  }

  get state() {
    return this._state;
  }

  set state(s) {
		this._state = s;
    this.render();
  }

  connectedCallback() {
    this.render();
    zeroFux.setReducers(actionTypes, reducers, this);
  }

  render() {
    const counterText = document.createTextNode(this.state);
    this.shadowRoot.innerHTML = '';
    this.shadowRoot.appendChild(counterText);
  }
}

window.customElements.define('my-counter', Counter);

class SideEffects {
  run() {
    zeroFux.dispatcher.addEventListener('ADD_TEN_IN_THREE', () => {
      window.setTimeout(() => zeroFux.dispatch({
        type: 'INCREMENT_X',
        payload: 10
      }), 3000);
    });
  }
}

const sideEffects = new SideEffects();
sideEffects.run();

const incButton = document.querySelector('.incButton');
const decButton = document.querySelector('.decButton');
const decaIncButton = document.querySelector('.decaIncButton');

incButton.addEventListener('click', e => zeroFux.dispatch({ type: 'INCREMENT' }));
decButton.addEventListener('click', e => zeroFux.dispatch({ type: 'DECREMENT' }));
decaIncButton.addEventListener('click', e => zeroFux.dispatch({ type: 'ADD_TEN_IN_THREE' }));

              
            
!
999px

Console