leptos-use/src/use_element_hover.rs

use crate::core::ElementMaybeSignal;
use crate::{use_event_listener_with_options, UseEventListenerOptions};
use cfg_if::cfg_if;
use default_struct_builder::DefaultBuilder;
use leptos::ev::{mouseenter, mouseleave};
use leptos::leptos_dom::helpers::TimeoutHandle;
use leptos::*;

cfg_if! { if #[cfg(not(feature = "ssr"))] {
    use std::time::Duration;
}}

/// Reactive element's hover state.
///
/// ## Demo
///
/// [Link to Demo](https://github.com/Synphonyte/leptos-use/tree/main/examples/use_element_hover)
///
/// ## Usage
///
/// ```
/// # use leptos::*;
/// # use leptos::html::Button;
/// # use leptos_use::use_element_hover;
/// #
/// # #[component]
/// # fn Demo() -> impl IntoView {
/// let el = create_node_ref::<Button>();
/// let is_hovered = use_element_hover(el);
///
/// view! {
///     <button node_ref=el>{ move || format!("{:?}", is_hovered.get()) }</button>
/// }
/// # }
/// ```
///
/// ## Server-Side Rendering
///
/// On the server this returns a `Signal` that always contains the value `false`.
pub fn use_element_hover<El, T>(el: El) -> Signal<bool>
where
    El: Clone,
    El: Into<ElementMaybeSignal<T, web_sys::EventTarget>>,
    T: Into<web_sys::EventTarget> + Clone + 'static,
{
    use_element_hover_with_options(el, UseElementHoverOptions::default())
}

/// Version of [`use_element_hover`] that takes a `UseElementHoverOptions`. See [`use_element_hover`] for how to use.

#[cfg_attr(feature = "ssr", allow(unused_variables, unused_mut))]
pub fn use_element_hover_with_options<El, T>(
    el: El,
    options: UseElementHoverOptions,
) -> Signal<bool>
where
    El: Clone,
    El: Into<ElementMaybeSignal<T, web_sys::EventTarget>>,
    T: Into<web_sys::EventTarget> + Clone + 'static,
{
    let UseElementHoverOptions {
        delay_enter,
        delay_leave,
    } = options;

    let (is_hovered, set_hovered) = create_signal(false);

    let mut timer: Option<TimeoutHandle> = None;

    let mut toggle = move |entering: bool| {
        cfg_if! { if #[cfg(not(feature = "ssr"))] {
            let delay = if entering { delay_enter } else { delay_leave };

            if let Some(handle) = timer.take() {
                handle.clear();
            }

            if delay > 0 {
                timer = set_timeout_with_handle(
                    move || set_hovered.set(entering),
                    Duration::from_millis(delay),
                )
                .ok();
            } else {
                set_hovered.set(entering);
            }
        }}
    };

    let listener_options = UseEventListenerOptions::default().passive(true);

    let _ = use_event_listener_with_options(
        el.clone(),
        mouseenter,
        move |_| toggle(true),
        listener_options,
    );

    let _ =
        use_event_listener_with_options(el, mouseleave, move |_| toggle(false), listener_options);

    is_hovered.into()
}

/// Options for [`use_element_hover_with_options`].
#[derive(DefaultBuilder, Default)]
pub struct UseElementHoverOptions {
    /// The time in ms the mouse has to be hovered over the element before the signal is changed to `true`. Defaults to `0`.
    delay_enter: u64,

    /// The time in ms after the mouse has left the element before the signal is changed to `false`. Defaults to `0`.
    delay_leave: u64,
}