Trait SignalUpdate

pub trait SignalUpdate {
    type Value;

    // Required methods
    fn update(&self, f: impl FnOnce(&mut Self::Value));
    fn try_update<O>(&self, f: impl FnOnce(&mut Self::Value) -> O) -> Option<O>;
}

This trait allows updating the inner value of a signal.

Required Associated Types

type Value

The value held by the signal.

Required Methods

fn update(&self, f: impl FnOnce(&mut Self::Value))

Applies a function to the current value to mutate it in place and notifies subscribers that the signal has changed.

Note: update() does not auto-memoize, i.e., it will notify subscribers even if the value has not actually changed.

fn try_update<O>(&self, f: impl FnOnce(&mut Self::Value) -> O) -> Option<O>

Applies a function to the current value to mutate it in place and notifies subscribers that the signal has changed. Returns [Some(O)] if the signal is still valid, None otherwise.

Note: update() does not auto-memoize, i.e., it will notify subscribers even if the value has not actually changed.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl SignalUpdate for Trigger

type Value = ()

impl<S, T> SignalUpdate for Resource<S, T>

type Value = Option<T>

impl<T> SignalUpdate for RwSignal<T>

Examples

let count = create_rw_signal(0);

// notifies subscribers
count.update(|n| *n = 1); // it's easier just to call set_count.set(1), though!
assert_eq!(count.get(), 1);

// you can include arbitrary logic in this update function
// also notifies subscribers, even though the value hasn't changed
count.update(|n| {
    if *n > 3 {
        *n += 1
    }
});
assert_eq!(count.get(), 1);

type Value = T

impl<T> SignalUpdate for WriteSignal<T>

Examples

let (count, set_count) = create_signal(0);

// notifies subscribers
set_count.update(|n| *n = 1); // it's easier just to call set_count.set(1), though!
assert_eq!(count.get(), 1);

// you can include arbitrary logic in this update function
// also notifies subscribers, even though the value hasn't changed
set_count.update(|n| if *n > 3 { *n += 1 });
assert_eq!(count.get(), 1);

type Value = T