function pathIsActive(pathname, currentPathname) {
	  // Normalize leading slash for consistency. Leading slash on pathname has
	  // already been normalized in isActive. See caveat there.
	  if (currentPathname.charAt(0) !== '/') {
	    currentPathname = '/' + currentPathname;
	  }

	  // Normalize the end of both path names too. Maybe `/foo/` shouldn't show
	  // `/foo` as active, but in this case, we would already have failed the
	  // match.
	  if (pathname.charAt(pathname.length - 1) !== '/') {
	    pathname += '/';
	  }
	  if (currentPathname.charAt(currentPathname.length - 1) !== '/') {
	    currentPathname += '/';
	  }

	  return currentPathname === pathname;
	}
Returns true if the current pathname matches the supplied one, net of
leading and trailing slash normalization. This is sufficient for an
indexOnly route match.