ponyfills.js

// we augment the window.history instance so that it will dispatch an event when using push/replace
// this allows us to create event stream and listen to all history state changes
export const patchHistory = history => {
  const wrap = m => (state, title, url) => {
    m.call(history, state, title, url);
    let e = new Event(m.name.toLowerCase());
    e.state = state;
    dispatchEvent(e);
  };

  history.pushState = wrap(history.pushState);
  history.replaceState = wrap(history.replaceState);
  return history;
};