Reason Routing

component.re

let getRouteComponent: ReasonReact.Router.url => ReasonReact.reactElement =
  (url) =>
    switch (MainRoutes.match(url)) {
    | Home(_url) => <Page message="Home" />
    | Admin(route) => <AdminRoot route />
    | NotFound(_url) => <Page message="404" />
    };

routes.re

open ReasonReact.Router;

module type RouteType = {type t; let match: url => t;};

module AdminRoutes: RouteType = {
  type t =
    | Root(url)
    | Transactions(option(string), url)
    | Members(option(string), url)
    | NotFound(url);
  let match = (url) =>
    switch url.path {
    | [] => Root(url)
    | ["transactions"] => Transactions(None, url)
    | ["transactions", id] => Transactions(Some(id), url)
    | ["members"] => Members(None, url)
    | ["members", id] => Members(Some(id), url)
    | _ => NotFound(url)
    };
};

module MainRoutes: RouteType = {
  type t =
    | Home(url)
    | Admin(AdminRoutes.t)
    | NotFound(url);
  let match = (url) =>
    switch url.path {
    | [] => Home(url)
    | ["admin", ...rest] => Admin(AdminRoutes.match({...url, path: rest}))
    | _ => NotFound(url)
    };
};