Struct Signal 

pub struct Signal<T> { /* private fields */ }

A piece of state that lives in the browser.

A signal is created with signal during a server render and read or written in runtime expressions, where it is reactive: an expression re-runs in the browser whenever a signal it read changes. A signal is cheap to clone, and every clone is the same signal: runtime expressions clone the signals they capture, so any number of them can capture one, a component takes one as a &Signal<T> prop, and a shard takes one as a Signal<T> parameter passed as $(signal).

A signal can also be read on the server, outside any runtime expression. get and read are tracked reads: they make the body’s content depend on the signal, so that a change re-runs the page, or the innermost shard enclosing the read, with the signal’s current value. get_untracked and read_untracked read the value without that dependency. Every value read on the server is untrusted user input, chosen by the client like a shard argument.

Implementations

impl<T> Signal<T>

pub fn read(&self) -> &T

Borrows the current value, tracking the signal as a dependency of the body reading it.

The body’s content is marked as depending on the signal, so the browser runtime re-runs the page, or the innermost shard enclosing the read, when the signal changes. Reading the same signal any number of times in one body marks its content once.

Panics

Panics when called outside a page, layout, component, or shard body, like signal.

pub fn read_untracked(&self) -> &T

Borrows the current value without tracking the signal.

A change to the signal does not re-run the body that read it this way. It can be called anywhere, not just inside a body.

impl<T> Signal<T>

where T: Clone,

pub fn get(&self) -> T

Clones the current value, tracking the signal as a dependency of the body reading it.

This is read for a value the body wants to own; the same tracking rules apply.

Panics

Panics when called outside a page, layout, component, or shard body, like signal.

pub fn get_untracked(&self) -> T

Clones the current value without tracking the signal.

This is read_untracked for a value the body wants to own.

Trait Implementations

impl<T> Clone for Signal<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for Signal<T>

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

Formats the value using the given formatter.

impl<T> Surrogated for Signal<T>

type Surrogate = SignalSurrogate<T>

fn into_surrogate(self) -> Self::Surrogate

impl<'__lifetime, T> Surrogated for &'__lifetime Signal<T>

type Surrogate = &'__lifetime SignalSurrogate<T>

fn into_surrogate(self) -> Self::Surrogate

impl<'__lifetime, T> Surrogated for &'__lifetime mut Signal<T>

type Surrogate = &'__lifetime mut SignalSurrogate<T>

fn into_surrogate(self) -> Self::Surrogate