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use wasm_bindgen::{prelude::*, JsCast};
use web_sys::Element;
use yew::prelude::*;
use super::use_raf_state;
use crate::web_sys_ext::{ResizeObserver, ResizeObserverEntry};
/// A sensor hook that tracks an HTML element's dimensions using the `ResizeObserver` API.
///
/// # Example
///
/// ```rust
/// # use yew::prelude::*;
/// #
/// use yew_hooks::prelude::*;
///
/// #[function_component(UseSize)]
/// fn size() -> Html {
/// let node = use_node_ref();
/// let state = use_size(node.clone());
///
/// html! {
/// <div ref={node}>
/// <b>{ " Width: " }</b>
/// { state.0 }
/// <b>{ " Height: " }</b>
/// { state.1 }
/// </div>
/// }
/// }
/// ```
#[hook]
pub fn use_size(node: NodeRef) -> (u32, u32) {
let state = use_raf_state(|| (0, 0));
{
let state = state.clone();
use_effect_with(node, move |node| {
let closure = Closure::wrap(Box::new(move |entries: Vec<ResizeObserverEntry>| {
for entry in &entries {
let element = entry.target();
state.set((
element.client_width() as u32,
element.client_height() as u32,
));
}
}) as Box<dyn Fn(Vec<ResizeObserverEntry>)>);
let observer = ResizeObserver::new(closure.as_ref().unchecked_ref()).unwrap_throw();
// Forget the closure to keep it alive
closure.forget();
if let Some(element) = &node.cast::<Element>() {
observer.observe(element);
}
move || observer.disconnect()
});
}
*state
}