dioxus-mirror/docs/router/src/reference/routing-update-callback.md

Routing Update Callback

In some cases we might want to run custom code when the current route changes. For this reason, the RouterConfiguration exposes an on_update field.

How does the callback behave?

The on_update is called whenever the current routing information changes. It is called after the router updated its internal state, but before depended components and hooks are updated.

If the callback returns a NavigationTarget, the router will replace the current location with the specified target. It will not call the on_update again.

If at any point the router encounters a navigation failure, it will go to the appropriate state without calling the on_update. It doesn't matter if the invalid target initiated the navigation, was found as a redirect target or returned by the on_update itself.

Code Example

# // Hidden lines (like this one) make the documentation tests work.
# extern crate dioxus;
# extern crate dioxus_router;
# extern crate dioxus_ssr;
#
use std::sync::Arc;

use dioxus::prelude::*;
use dioxus_router::prelude::*;

fn App(cx: Scope) -> Element {
    use_router(
        cx,
        &|| RouterConfiguration {
            # synchronous: true,
            on_update: Some(Arc::new(|state| -> Option<NavigationTarget> {
                if state.path == "/" {
                    return Some("/home".into());
                }

                None
            })),
            ..Default::default()
        },
        &|| Segment::empty().fixed("home", comp(Content))
    );

    render! {
        Outlet { }
    }
}

fn Content(cx: Scope) -> Element {
    render! {
        p { "Some content" }
    }
}
#
# let mut vdom = VirtualDom::new(App);
# vdom.rebuild();
# assert_eq!(dioxus_ssr::render(&mut vdom), "<p>Some content</p>");