Request Animation frame web_sys 0.3

use wasm_bindgen::JsCast;
use wasm_bindgen::closure::Closure;
use web_sys::{Document, HtmlCanvasElement, HtmlElement, Window};


fn window() -> Window {
    web_sys::window().expect("no global `window` exists")
}

fn document() -> Document {
    window()
        .document()
        .expect("should have a document on window")
}

fn body() -> HtmlElement {
    document().body().expect("document should have a body")
}

fn request_animation_frame(f: &Closure<dyn FnMut()>) {
    window()
        .request_animation_frame(f.as_ref().unchecked_ref())
        .expect("should register `requestAnimationFrame` OK");
}

fn foo() {

        web_sys::console::log_1(&"hello wasm".into());

        let f: Rc<RefCell<Option<Closure<dyn FnMut()>>>> = Rc::new(RefCell::new(None));
        let g = f.clone();
        let h = g.clone();

        let mut i = 0;
        let closure = Closure::wrap(Box::new(move || {
            if i > 300 {
                body().set_text_content(Some("All done!"));
                return;
            }

            // Set the body's text content to how many times this
            // requestAnimationFrame callback has fired.
            i += 1;
            request_animation_frame(h.borrow().as_ref().unwrap());
        }) as Box<dyn FnMut()>);
        *g.borrow_mut() = Some(closure);

        request_animation_frame(f.borrow().as_ref().unwrap());
}