Struct LazyComponent 

pub struct LazyComponent<T: Clone + PartialEq + 'static> { /* private fields */ }

A lazy component that defers factory invocation until first access.

Use LazyComponent::new(factory) to construct, then get() to read (which triggers the factory on first call) or prefetch() to trigger without reading.

Why use Rc<dyn Fn() -> T>?

Because the factory must be callable multiple times (e.g. after a reset()), and dyn Fn lets the user pass any closure that produces a T. The factory is stored as Rc<dyn Fn() -> T> (not Box<dyn Fn>) so LazyComponent can be cloned cheaply and shared between hook contexts.

Implementations

impl<T: Clone + PartialEq + 'static> LazyComponent<T>

Inherent implementation of LazyComponent.

pub fn new<F>(factory: F) -> Self

where F: Fn() -> T + 'static,

Creates a new lazy component with the given factory. The factory is NOT called yet.

Arguments

• F: Fn() -> T + 'static - A generic type parameter.

pub fn prefetch(&self)

Triggers the factory without reading the value. Idempotent: calling prefetch() twice does not run the factory twice.

pub fn get(&self) -> Option<T>

Reads the value, calling the factory on the first call. Subsequent calls return the cached value.

Returns

• Option<T> - The current value (or a snapshot thereof).

pub fn loaded(&self) -> Option<T>

Returns the loaded value, or None if the state is Pending, Loading, or Failed.

Use Self::get (which runs the factory if needed) when you want the value-or-None semantics. This method is for the rare case where you already know the value was loaded and you want to inspect it without triggering a synchronous factory call.

Returns

• Option<T> - Some(value) when an asynchronously-loaded value is available, otherwise None.

pub fn reset(&self)

Resets the lazy component to Pending. The next get() call will re-run the factory.

pub fn change_factory<F>(&self, factory: F)

where F: Fn() -> T + 'static,

Replaces the factory. The state is reset to Pending so the next get() runs the new factory.

Arguments

• F: Fn() -> T + 'static - A generic type parameter.

impl<T: Clone + PartialEq + 'static> LazyComponent<T>

pub fn get_state(&self) -> &Signal<LoadState<T>>

pub fn get_mut_state(&mut self) -> &mut Signal<LoadState<T>>

pub fn set_state(&mut self, val: Signal<LoadState<T>>) -> &mut Self

pub fn get_factory(&self) -> &Rc<dyn Fn() -> T>

pub fn get_mut_factory(&mut self) -> &mut Rc<dyn Fn() -> T>

pub fn set_factory(&mut self, val: Rc<dyn Fn() -> T>) -> &mut Self

Trait Implementations

impl<T: Clone + Clone + PartialEq + 'static> Clone for LazyComponent<T>

fn clone(&self) -> LazyComponent<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Clone + PartialEq + Debug + 'static> Debug for LazyComponent<T>

Debug formatting for LazyComponent.

fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult

Formats the LazyComponent via the supplied formatter.

Arguments

• &mut Formatter<'_> - The formatter receiving the formatted output.

Returns

• FmtResult - Result of the formatting operation.