dioxus/examples/suspense.rs

//! Suspense in Dioxus
//!
//! Currently, `rsx!` does not accept futures as values. To achieve the functionality
//! of suspense, we need to make a new component that performs its own suspense
//! handling.
//!
//! In this example, we render the `Doggo` component which starts a future that
//! will cause it to fetch a random dog image from the Dog API. Since the data
//! is not ready immediately, we render some loading text.
//!
//! We can achieve the majoirty of suspense functionality by composing "suspenseful"
//! primitives in our own custom components.

use dioxus::prelude::*;

fn main() {
    use dioxus::desktop::tao::dpi::LogicalSize;
    dioxus::desktop::launch_cfg(app, |cfg| {
        cfg.with_window(|w| {
            w.with_title("Doggo Fetcher")
                .with_inner_size(LogicalSize::new(600.0, 800.0))
        })
    });
}

#[derive(serde::Deserialize)]
struct DogApi {
    message: String,
}

fn app(cx: Scope) -> Element {
    cx.render(rsx! {
        div {
            h1 {"Dogs are very important"}
            p {
                "The dog or domestic dog (Canis familiaris[4][5] or Canis lupus familiaris[5])" 
                "is a domesticated descendant of the wolf which is characterized by an upturning tail." 
                "The dog derived from an ancient, extinct wolf,[6][7] and the modern grey wolf is the"
                "dog's nearest living relative.[8] The dog was the first species to be domesticated,[9][8]"
                "by hunter–gatherers over 15,000 years ago,[7] before the development of agriculture.[1]"
            }

            h3 { "Illustrious Dog Photo" }
            Doggo { }
        }
    })
}

/// This component will re-render when the future has finished
/// Suspense is achieved my moving the future into only the component that
/// actually renders the data.
fn Doggo(cx: Scope) -> Element {
    let fut = use_future(&cx, || async move {
        reqwest::get("https://dog.ceo/api/breeds/image/random/")
            .await
            .unwrap()
            .json::<DogApi>()
            .await
    });

    cx.render(match fut.value() {
        Some(Ok(resp)) => rsx! {
            button {
                onclick: move |_| fut.restart(),
                "Click to fetch another doggo"
            }
            div {
                img {
                    max_width: "500px",
                    max_height: "500px",
                    src: "{resp.message}",
                }
            }
        },
        Some(Err(_)) => rsx! { div { "loading dogs failed" } },
        None => rsx! { div { "loading dogs..." } },
    })
}