message: Fixes non-root base paths (again)
  History adds the basepath to absolute paths,
  so we have to strip it on our own or else we are navigated to
  `/basePath/basePath/`.
diff: +import * as _ from 'lodash';
  import { createBrowserHistory, createMemoryHistory } from 'history';
  let createHistory;
  @@ -16,4 +17,15 @@ try {
  export const history = createHistory({basename: window.SERVER_FLAGS.basePath});
  +const removeBasePath = (url ='/') => _.startsWith(url, window.SERVER_FLAGS.basePath)
  + ? url.slice(window.SERVER_FLAGS.basePath.length - 1)
  + : url;
  +
  +// Monkey patch history to slice off the base path
  +history.__replace__ = history.replace;
  +history.replace = url => history.__replace__(removeBasePath(url));
  +
  +history.__push__ = history.push;
  +history.push = url => history.__push__(removeBasePath(url));
  +
  export const getQueryArgument = arg => new URLSearchParams(window.location.search).get(arg);
  