export const normalizeLink = (to: string, location = window.location) => {
  to = to || '';

  if (to && to[0] === '#') {
    to = location.pathname + location.search + to;
  } else if (to && to[0] === '?') {
    to = location.pathname + to;
  }

  const idx = to.indexOf('?');
  const idx2 = to.indexOf('#');
  let pathname = ~idx
    ? to.substring(0, idx)
    : ~idx2
    ? to.substring(0, idx2)
    : to;
  let search = ~idx ? to.substring(idx, ~idx2 ? idx2 : undefined) : '';
  let hash = ~idx2 ? to.substring(idx2) : location.hash;

  if (!pathname) {
    pathname = location.pathname;
  } else if (pathname[0] != '/' && !/^https?\:\/\//.test(pathname)) {
    let relativeBase = location.pathname;
    const paths = relativeBase.split('/');
    paths.pop();
    let m;
    while ((m = /^\.\.?\//.exec(pathname))) {
      if (m[0] === '../') {
        paths.pop();
      }
      pathname = pathname.substring(m[0].length);
    }
    pathname = paths.concat(pathname).join('/');
  }

  return pathname + search + hash;
};