initialize reason react router

[@bs.send] external dispatchEvent : (Dom.window, Dom.event) => unit = "";
[@bs.new]  external makeEvent : ([@bs.string] [ | `popstate]) => Dom.event = "Event";

  let initializeRouter = () =>
    switch ([%external window]) {
    | None => ()
    | Some(window: Dom.window) =>   dispatchEvent(window, makeEvent(`popstate));
    };