CustomEvent based dispatch, listen and action dispatch

custom_events.js

export function dispatch(el, eventName, payload, options) {
  options || (options = {});
  el || (el = document);
  el = el.el || el;
  var event = new CustomEvent(eventName, {
    detail: payload || {},
    bubbles: options.bubbles !== false
  });
  el.dispatchEvent(event);
}

export function listen(el, eventName, callback) {
  el || (el = document);
  el = el.el || el;
  el.addEventListener(eventName, callback);
  return callback; // return callback reference for unbinding
}

export function dispatchAction(actionName, payload, el) {
  el || (el = document);
  const action = {
    action: actionName,
    payload: payload || {}
  };
  dispatch(el, 'action', action);
}

export function dispatcher(handler) {
  listen(document, 'action', e => {
    var action = e.detail.action;
    var payload = e.detail.payload || {};
    handler.call(this, action, Object.assign({}, payload));

    e.stopPropagation();
    return false;
  });
}