Struct ReadSignal

pub struct ReadSignal<T, S = SyncStorage> {
    pub(crate) inner: ArenaItem<ArcReadSignal<T>, S>,
}

An arena-allocated getter for a reactive signal.

A signal is a piece of data that may change over time, and notifies other code when it has changed.

This is an arena-allocated signal, which is Copy and is disposed when its reactive Owner cleans up. For a reference-counted signal that lives as long as a reference to it is alive, see ArcReadSignal.

Core Trait Implementations

• .get() clones the current value of the signal. If you call it within an effect, it will cause that effect to subscribe to the signal, and to re-run whenever the value of the signal changes.
  • .get_untracked() clones the value of the signal without reactively tracking it.
• .read() returns a guard that allows accessing the value of the signal by reference. If you call it within an effect, it will cause that effect to subscribe to the signal, and to re-run whenever the value of the signal changes.
  • .read_untracked() gives access to the current value of the signal without reactively tracking it.
• .with() allows you to reactively access the signal’s value without cloning by applying a callback function.
  • .with_untracked() allows you to access the signal’s value by applying a callback function without reactively tracking it.
• .to_stream() converts the signal to an async stream of values.
• ::from_stream() converts an async stream of values into a signal containing the latest value.

Examples

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

// calling .get() clones and returns the value
assert_eq!(count.get(), 0);
// calling .read() accesses the value by reference
assert_eq!(count.read(), 0);

Fields

inner: ArenaItem<ArcReadSignal<T>, S>

Trait Implementations

impl<T, S> Clone for ReadSignal<T, S>

fn clone(&self) -> ReadSignal<T, S>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T, S> Debug for ReadSignal<T, S>

where S: Debug,

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

Formats the value using the given formatter.

impl<T, S> DefinedAt for ReadSignal<T, S>

fn defined_at(&self) -> Option<&'static Location<'static>>

Returns the location at which the signal was defined. This is usually simply None in release mode.

impl<T, S> Dispose for ReadSignal<T, S>

fn dispose(self)

Disposes of the signal. This:

impl<T, S> Fn() for ReadSignal<T, S>

where ReadSignal<T, S>: Get, S: Storage<T> + Storage<Option<T>> + Storage<SignalTypes<Option<T>, S>>,

extern "rust-call" fn call( &self, _args: (), ) -> <ReadSignal<T, S> as FnOnce()>::Output

🔬This is a nightly-only experimental API. (fn_traits)

Performs the call operation.

impl<T, S> FnMut() for ReadSignal<T, S>

where ReadSignal<T, S>: Get, S: Storage<T> + Storage<Option<T>> + Storage<SignalTypes<Option<T>, S>>,

extern "rust-call" fn call_mut( &mut self, _args: (), ) -> <ReadSignal<T, S> as FnOnce()>::Output

🔬This is a nightly-only experimental API. (fn_traits)

Performs the call operation.

impl<T, S> FnOnce() for ReadSignal<T, S>

where ReadSignal<T, S>: Get, S: Storage<T> + Storage<Option<T>> + Storage<SignalTypes<Option<T>, S>>,

type Output = <ReadSignal<T, S> as Get>::Value

The returned type after the call operator is used.

extern "rust-call" fn call_once( self, _args: (), ) -> <ReadSignal<T, S> as FnOnce()>::Output

🔬This is a nightly-only experimental API. (fn_traits)

Performs the call operation.

impl<T> From<ArcReadSignal<T>> for ReadSignal<T>

where T: Send + Sync + 'static,

fn from(value: ArcReadSignal<T>) -> ReadSignal<T>

Converts to this type from the input type.

impl<T> From<ReadSignal<Option<T>>> for MaybeProp<T>

where T: Send + Sync,

fn from(value: ReadSignal<Option<T>>) -> MaybeProp<T>

Converts to this type from the input type.

impl<T> From<ReadSignal<Option<T>, LocalStorage>> for MaybeProp<T, LocalStorage>

where T: Send + Sync,

fn from( value: ReadSignal<Option<T>, LocalStorage>, ) -> MaybeProp<T, LocalStorage>

Converts to this type from the input type.

impl<T> From<ReadSignal<T>> for MaybeProp<T>

where T: Send + Sync + Clone,

fn from(value: ReadSignal<T>) -> MaybeProp<T>

Converts to this type from the input type.

impl<T> From<ReadSignal<T>> for MaybeSignal<T>

where T: Send + Sync,

fn from(value: ReadSignal<T>) -> MaybeSignal<T>

Converts to this type from the input type.

impl<T> From<ReadSignal<T>> for OptionalProp<Signal<T>>

where T: Send + Sync + 'static,

fn from(value: ReadSignal<T>) -> OptionalProp<Signal<T>>

Converts to this type from the input type.

impl<T> From<ReadSignal<T>> for Signal<T>

where T: Send + Sync + 'static,

fn from(value: ReadSignal<T>) -> Signal<T>

Converts to this type from the input type.

impl<T> From<ReadSignal<T, LocalStorage>> for MaybeProp<T, LocalStorage>

where T: Send + Sync + Clone,

fn from(value: ReadSignal<T, LocalStorage>) -> MaybeProp<T, LocalStorage>

Converts to this type from the input type.

impl<T> From<ReadSignal<T, LocalStorage>> for MaybeSignal<T, LocalStorage>

fn from(value: ReadSignal<T, LocalStorage>) -> MaybeSignal<T, LocalStorage>

Converts to this type from the input type.

impl<T> From<ReadSignal<T, LocalStorage>> for Signal<T, LocalStorage>

where T: 'static,

fn from(value: ReadSignal<T, LocalStorage>) -> Signal<T, LocalStorage>

Converts to this type from the input type.

impl<T, S> From<ReadSignal<T, S>> for ArcReadSignal<T>

where T: 'static, S: Storage<ArcReadSignal<T>>,

fn from(value: ReadSignal<T, S>) -> ArcReadSignal<T>

Converts to this type from the input type.

impl<T> FromLocal<ArcReadSignal<T>> for ReadSignal<T, LocalStorage>

where T: 'static,

fn from_local(value: ArcReadSignal<T>) -> ReadSignal<T, LocalStorage>

Converts between the types.

impl<T, S> Hash for ReadSignal<T, S>

fn hash<H>(&self, state: &mut H)

where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T, S> IntoInner for ReadSignal<T, S>

where S: Storage<ArcReadSignal<T>>,

type Value = T

The type of the value contained in the signal.

fn into_inner(self) -> Option<<ReadSignal<T, S> as IntoInner>::Value>

Returns the inner value if this is the only reference to the signal. Otherwise, returns None and drops this reference.

impl<T, S> IsDisposed for ReadSignal<T, S>

fn is_disposed(&self) -> bool

If true, the signal cannot be accessed without a panic.

impl<T, S> PartialEq for ReadSignal<T, S>

fn eq(&self, other: &ReadSignal<T, S>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T, S> ReadUntracked for ReadSignal<T, S>

where T: 'static, S: Storage<ArcReadSignal<T>>,

type Value = ReadGuard<T, Plain<T>>

The guard type that will be returned, which can be dereferenced to the value.

fn try_read_untracked( &self, ) -> Option<<ReadSignal<T, S> as ReadUntracked>::Value>

Returns the guard, or None if the signal has already been disposed.

fn read_untracked(&self) -> Self::Value

Returns the guard.

fn custom_try_read(&self) -> Option<Option<Self::Value>>

This is a backdoor to allow overriding the Read::try_read implementation despite it being auto implemented.

impl<T, St> Serialize for ReadSignal<T, St>

where T: Serialize + 'static, St: Storage<ArcReadSignal<T>>,

fn serialize<S>( &self, serializer: S, ) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl<T, S> Copy for ReadSignal<T, S>

impl<T, S> Eq for ReadSignal<T, S>