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use std::ops::Deref;
use std::{cell::RefCell, rc::Rc};
use gloo::render::{request_animation_frame, AnimationFrame};
use yew::prelude::*;
use super::use_unmount;
/// State handle for the [`use_raf_state`] hook.
pub struct UseRafStateHandle<T> {
inner: UseStateHandle<T>,
raf: Rc<RefCell<Option<AnimationFrame>>>,
}
impl<T> UseRafStateHandle<T>
where
T: 'static,
{
/// Replaces the value.
pub fn set(&self, value: T) {
let inner = self.inner.clone();
*self.raf.borrow_mut() = Some(request_animation_frame(move |_| {
inner.set(value);
}));
}
}
impl<T> Deref for UseRafStateHandle<T> {
type Target = T;
fn deref(&self) -> &Self::Target {
&self.inner
}
}
impl<T> Clone for UseRafStateHandle<T> {
fn clone(&self) -> Self {
Self {
inner: self.inner.clone(),
raf: self.raf.clone(),
}
}
}
impl<T> PartialEq for UseRafStateHandle<T>
where
T: PartialEq,
{
fn eq(&self, other: &Self) -> bool {
*self.inner == *other.inner
}
}
/// A state hook that only updates state in the callback of `requestAnimationFrame`.
///
/// # Example
///
/// ```rust
/// # use web_sys::Window;
/// # use yew::prelude::*;
/// #
/// use yew_hooks::prelude::*;
///
/// #[function_component(UseRafState)]
/// fn raf_state() -> Html {
/// let state = use_raf_state(|| (0f64, 0f64));
///
/// {
/// let state = state.clone();
/// use_event_with_window("resize", move |e: Event| {
/// let window: Window = e.target_unchecked_into();
/// state.set((
/// window.inner_width().unwrap().as_f64().unwrap(),
/// window.inner_height().unwrap().as_f64().unwrap(),
/// ));
/// });
/// }
///
/// html! {
/// <>
/// <b>{ " Width: " }</b>
/// { state.0 }
/// <b>{ " Height: " }</b>
/// { state.1 }
/// </>
/// }
/// }
/// ```
#[hook]
pub fn use_raf_state<T, F>(init_fn: F) -> UseRafStateHandle<T>
where
T: 'static,
F: FnOnce() -> T,
{
let inner = use_state(init_fn);
let raf = use_mut_ref(|| None);
{
let raf = raf.clone();
use_unmount(move || {
*raf.borrow_mut() = None;
});
}
UseRafStateHandle { inner, raf }
}