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use crate::{html::ElementDescriptor, HtmlElement};
use leptos_reactive::{create_render_effect, signal_prelude::*};
use std::cell::Cell;
/// Contains a shared reference to a DOM node created while using the `view`
/// macro to create your UI.
///
/// ```
/// # use leptos::{*, logging::log};
/// use leptos::html::Input;
///
/// #[component]
/// pub fn MyComponent() -> impl IntoView {
/// let input_ref = create_node_ref::<Input>();
///
/// let on_click = move |_| {
/// let node =
/// input_ref.get().expect("input_ref should be loaded by now");
/// // `node` is strongly typed
/// // it is dereferenced to an `HtmlInputElement` automatically
/// log!("value is {:?}", node.value())
/// };
///
/// view! {
/// <div>
/// // `node_ref` loads the input
/// <input _ref=input_ref type="text"/>
/// // the button consumes it
/// <button on:click=on_click>"Click me"</button>
/// </div>
/// }
/// }
/// ```
#[repr(transparent)]
pub struct NodeRef<T: ElementDescriptor + 'static>(
RwSignal<Option<HtmlElement<T>>>,
);
/// Creates a shared reference to a DOM node created while using the `view`
/// macro to create your UI.
///
/// ```
/// # use leptos::{*, logging::log};
/// use leptos::html::Input;
///
/// #[component]
/// pub fn MyComponent() -> impl IntoView {
/// let input_ref = create_node_ref::<Input>();
///
/// let on_click = move |_| {
/// let node =
/// input_ref.get().expect("input_ref should be loaded by now");
/// // `node` is strongly typed
/// // it is dereferenced to an `HtmlInputElement` automatically
/// log!("value is {:?}", node.value())
/// };
///
/// view! {
/// <div>
/// // `node_ref` loads the input
/// <input _ref=input_ref type="text"/>
/// // the button consumes it
/// <button on:click=on_click>"Click me"</button>
/// </div>
/// }
/// }
/// ```
#[inline(always)]
pub fn create_node_ref<T: ElementDescriptor + 'static>() -> NodeRef<T> {
NodeRef(create_rw_signal(None))
}
impl<T: ElementDescriptor + 'static> NodeRef<T> {
/// Creates a shared reference to a DOM node created while using the `view`
/// macro to create your UI.
///
/// This is identical to [`create_node_ref`].
///
/// ```
/// # use leptos::{*, logging::log};
///
/// use leptos::html::Input;
///
/// #[component]
/// pub fn MyComponent() -> impl IntoView {
/// let input_ref = NodeRef::<Input>::new();
///
/// let on_click = move |_| {
/// let node =
/// input_ref.get().expect("input_ref should be loaded by now");
/// // `node` is strongly typed
/// // it is dereferenced to an `HtmlInputElement` automatically
/// log!("value is {:?}", node.value())
/// };
///
/// view! {
/// <div>
/// // `node_ref` loads the input
/// <input _ref=input_ref type="text"/>
/// // the button consumes it
/// <button on:click=on_click>"Click me"</button>
/// </div>
/// }
/// }
/// ```
#[inline(always)]
#[track_caller]
pub fn new() -> Self {
create_node_ref()
}
/// Gets the element that is currently stored in the reference.
///
/// This tracks reactively, so that node references can be used in effects.
/// Initially, the value will be `None`, but once it is loaded the effect
/// will rerun and its value will be `Some(Element)`.
#[track_caller]
#[inline(always)]
pub fn get(&self) -> Option<HtmlElement<T>>
where
T: Clone,
{
self.0.get()
}
/// Gets the element that is currently stored in the reference.
///
/// This **does not** track reactively.
#[track_caller]
#[inline(always)]
pub fn get_untracked(&self) -> Option<HtmlElement<T>>
where
T: Clone,
{
self.0.get_untracked()
}
#[doc(hidden)]
/// Loads an element into the reference. This tracks reactively,
/// so that effects that use the node reference will rerun once it is loaded,
/// i.e., effects can be forward-declared.
#[track_caller]
pub fn load(&self, node: &HtmlElement<T>)
where
T: Clone,
{
self.0.update(|current| {
if current.is_some() {
crate::debug_warn!(
"You are setting a NodeRef that has already been filled. \
It’s possible this is intentional, but it’s also \
possible that you’re accidentally using the same NodeRef \
for multiple _ref attributes."
);
}
*current = Some(node.clone());
});
}
/// Runs the provided closure when the `NodeRef` has been connected
/// with it's [`HtmlElement`].
#[inline(always)]
pub fn on_load<F>(self, f: F)
where
T: Clone,
F: FnOnce(HtmlElement<T>) + 'static,
{
let f = Cell::new(Some(f));
create_render_effect(move |_| {
if let Some(node_ref) = self.get() {
f.take().unwrap()(node_ref);
}
});
}
}
impl<T: ElementDescriptor> Clone for NodeRef<T> {
fn clone(&self) -> Self {
*self
}
}
impl<T: ElementDescriptor + 'static> Copy for NodeRef<T> {}
impl<T: ElementDescriptor + 'static> Default for NodeRef<T> {
fn default() -> Self {
Self::new()
}
}
cfg_if::cfg_if! {
if #[cfg(feature = "nightly")] {
impl<T: Clone + ElementDescriptor + 'static> FnOnce<()> for NodeRef<T> {
type Output = Option<HtmlElement<T>>;
#[inline(always)]
extern "rust-call" fn call_once(self, _args: ()) -> Self::Output {
self.get()
}
}
impl<T: Clone + ElementDescriptor + 'static> FnMut<()> for NodeRef<T> {
#[inline(always)]
extern "rust-call" fn call_mut(&mut self, _args: ()) -> Self::Output {
self.get()
}
}
impl<T: Clone + ElementDescriptor + Clone + 'static> Fn<()> for NodeRef<T> {
#[inline(always)]
extern "rust-call" fn call(&self, _args: ()) -> Self::Output {
self.get()
}
}
}
}