Struct ArcSignal 

pub struct ArcSignal<T, S = SyncStorage>
where
    T: 'static,
    S: Storage<T>,
{ /* private fields */ }

A wrapper for any kind of reference-counted reactive signal: an ArcReadSignal, ArcMemo, ArcRwSignal, or derived signal closure, or a plain value of the same type

This allows you to create APIs that take T or any reactive value that returns T as an argument, rather than adding a generic F: Fn() -> T.

Values can be accessed with the same function call, read(), with(), and get() APIs as other signals.

Important Notes about Derived Signals

Signal::derive() is simply a way to box and type-erase a “derived signal,” which is a plain closure that accesses one or more signals. It does not cache the value of that computation. Accessing the value of a Signal<_> that is created using Signal::derive() will run the closure again every time you call .read(), .with(), or .get().

If you want the closure to run the minimal number of times necessary to update its state, and then to cache its value, you should use a Memo (and convert it into a Signal<_>) rather than using Signal::derive().

Note that for many computations, it is nevertheless less expensive to use a derived signal than to create a separate memo and to cache the value: creating a new reactive node and taking the lock on that cached value whenever you access the signal is more expensive than simply re-running the calculation in many cases.

Implementations

impl<T> ArcSignal<T>

where SyncStorage: Storage<T>,

pub fn derive( derived_signal: impl Fn() -> T + Send + Sync + 'static, ) -> ArcSignal<T>

Wraps a derived signal, i.e., any computation that accesses one or more reactive signals.

let (count, set_count) = arc_signal(2);
let double_count = ArcSignal::derive({
    let count = count.clone();
    move || count.get() * 2
});

// this function takes any kind of wrapped signal
fn above_3(arg: &ArcSignal<i32>) -> bool {
    arg.get() > 3
}

assert_eq!(above_3(&count.into()), false);
assert_eq!(above_3(&double_count), true);

pub fn stored(value: T) -> ArcSignal<T>

Moves a static, nonreactive value into a signal, backed by ArcStoredValue.

impl<T> ArcSignal<T, LocalStorage>

where T: 'static,

pub fn derive_local( derived_signal: impl Fn() -> T + 'static, ) -> ArcSignal<T, LocalStorage>

Wraps a derived signal. Works like Signal::derive but uses LocalStorage.

pub fn stored_local(value: T) -> ArcSignal<T, LocalStorage>

Moves a static, nonreactive value into a signal, backed by ArcStoredValue. Works like Signal::stored but uses LocalStorage.

Trait Implementations

impl<V> AddAnyAttr for ArcSignal<V>

where V: RenderHtml + Clone + Send + Sync + 'static, <V as Render>::State: 'static, ArcSignal<V>: Get<Value = V>,

type Output<SomeNewAttr: Attribute> = ArcSignal<V>

The new type once the attribute has been added.

fn add_any_attr<NewAttr>( self, _attr: NewAttr, ) -> <ArcSignal<V> as AddAnyAttr>::Output<NewAttr>

where NewAttr: Attribute,

Adds an attribute to the view.

impl<V> AttributeValue for ArcSignal<V>

where V: AttributeValue + Send + Sync + Clone + 'static, <V as AttributeValue>::State: 'static, ArcSignal<V>: Get<Value = V>,

type AsyncOutput = ArcSignal<V>

The type once all async data have loaded.

type State = RenderEffect<<V as AttributeValue>::State>

The state that should be retained between building and rebuilding.

type Cloneable = ArcSignal<V>

A version of the value that can be cloned. This can be the same type, or a reference-counted type. Generally speaking, this does not need to refer to the same data, but should behave in the same way. So for example, making an event handler cloneable should probably make it reference-counted (so that a FnMut() continues mutating the same closure), but making a String cloneable does not necessarily need to make it an Arc<str>, as two different clones of a String will still have the same value.

type CloneableOwned = ArcSignal<V>

A cloneable type that is also 'static. This is used for spreading across types when the spreadable attribute needs to be owned. In some cases (&'a str to Arc<str>, etc.) the owned cloneable type has worse performance than the cloneable type, so they are separate.

fn html_len(&self) -> usize

An approximation of the actual length of this attribute in HTML.

fn to_html(self, key: &str, buf: &mut String)

Renders the attribute value to HTML.

fn to_template(_key: &str, _buf: &mut String)

Renders the attribute value to HTML for a <template>.

fn hydrate<const FROM_SERVER: bool>( self, key: &str, el: &Element, ) -> <ArcSignal<V> as AttributeValue>::State

Adds interactivity as necessary, given DOM nodes that were created from HTML that has either been rendered on the server, or cloned for a <template>.

fn build( self, el: &Element, key: &str, ) -> <ArcSignal<V> as AttributeValue>::State

Adds this attribute to the element during client-side rendering.

fn rebuild(self, key: &str, state: &mut <ArcSignal<V> as AttributeValue>::State)

Applies a new value for the attribute.

fn into_cloneable(self) -> <ArcSignal<V> as AttributeValue>::Cloneable

Converts this attribute into an equivalent that can be cloned.

fn into_cloneable_owned( self, ) -> <ArcSignal<V> as AttributeValue>::CloneableOwned

Converts this attributes into an equivalent that can be cloned and is 'static.

fn dry_resolve(&mut self)

“Runs” the attribute without other side effects. For primitive types, this is a no-op. For reactive types, this can be used to gather data about reactivity or about asynchronous data that needs to be loaded.

async fn resolve(self) -> <ArcSignal<V> as AttributeValue>::AsyncOutput

“Resolves” this into a form that is not waiting for any asynchronous data.

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

where S: Storage<T>,

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

where S: Storage<T>,

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

Formats the value using the given formatter.

impl<T> Default for ArcSignal<T>

where T: Default + Send + Sync + 'static,

fn default() -> ArcSignal<T>

Returns the “default value” for a type.

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

where S: Storage<T>,

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> From<ArcMemo<T, S>> for ArcSignal<T, S>

where S: Storage<T>,

fn from(value: ArcMemo<T, S>) -> ArcSignal<T, S>

Converts to this type from the input type.

impl<T> From<ArcReadSignal<T>> for ArcSignal<T>

where T: Send + Sync,

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

Converts to this type from the input type.

impl<T> From<ArcRwSignal<T>> for ArcSignal<T>

where T: Send + Sync,

fn from(value: ArcRwSignal<T>) -> ArcSignal<T>

Converts to this type from the input type.

impl<T> From<ArcSignal<T>> for Signal<T>

where T: Send + Sync + 'static,

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

Converts to this type from the input type.

impl<V> From<ArcSignal<V>> for TextProp

where V: Into<Oco<'static, str>> + Clone + Send + Sync + 'static, ArcSignal<V>: Get<Value = V>,

fn from(s: ArcSignal<V>) -> TextProp

Converts to this type from the input type.

impl<T, S> From<Memo<T, S>> for ArcSignal<T, S>

where S: Storage<ArcMemo<T, S>> + Storage<T>,

fn from(value: Memo<T, S>) -> ArcSignal<T, S>

Converts to this type from the input type.

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

where S: Storage<ArcReadSignal<T>> + Storage<T>,

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

Converts to this type from the input type.

impl<T, S> From<RwSignal<T, S>> for ArcSignal<T, S>

where S: Storage<ArcRwSignal<T>> + Storage<ArcReadSignal<T>> + Storage<T>,

fn from(value: RwSignal<T, S>) -> ArcSignal<T, S>

Converts to this type from the input type.

impl<T, S> From<Signal<T, S>> for ArcSignal<T, S>

where S: Storage<SignalTypes<T, S>> + Storage<T>,

fn from(value: Signal<T, S>) -> ArcSignal<T, S>

Converts to this type from the input type.

impl<T> From<T> for ArcSignal<T>

where T: Send + Sync + 'static,

fn from(value: T) -> ArcSignal<T>

Converts to this type from the input type.

impl<T> FromLocal<ArcSignal<T, LocalStorage>> for Signal<T, LocalStorage>

where T: 'static,

fn from_local(value: ArcSignal<T, LocalStorage>) -> Signal<T, LocalStorage>

Converts between the types.

impl<V> InnerHtmlValue for ArcSignal<V>

where V: InnerHtmlValue + Clone + Send + Sync + 'static, <V as InnerHtmlValue>::State: 'static, ArcSignal<V>: Get<Value = V>,

type AsyncOutput = ArcSignal<V>

The type after all async data have resolved.

type State = RenderEffect<<V as InnerHtmlValue>::State>

The view state retained between building and rebuilding.

type Cloneable = ArcSignal<V>

An equivalent value that can be cloned.

type CloneableOwned = ArcSignal<V>

An equivalent value that can be cloned and is 'static.

fn html_len(&self) -> usize

The estimated length of the HTML.

fn to_html(self, buf: &mut String)

Renders the class to HTML.

fn to_template(_buf: &mut String)

Renders the class to HTML for a <template>.

fn hydrate<const FROM_SERVER: bool>( self, el: &Element, ) -> <ArcSignal<V> as InnerHtmlValue>::State

Adds interactivity as necessary, given DOM nodes that were created from HTML that has either been rendered on the server, or cloned for a <template>.

fn build(self, el: &Element) -> <ArcSignal<V> as InnerHtmlValue>::State

Adds this class to the element during client-side rendering.

fn rebuild(self, state: &mut <ArcSignal<V> as InnerHtmlValue>::State)

Updates the value.

fn into_cloneable(self) -> <ArcSignal<V> as InnerHtmlValue>::Cloneable

Converts this to a cloneable type.

fn into_cloneable_owned( self, ) -> <ArcSignal<V> as InnerHtmlValue>::CloneableOwned

Converts this to a cloneable, owned type.

fn dry_resolve(&mut self)

“Runs” the attribute without other side effects. For primitive types, this is a no-op. For reactive types, this can be used to gather data about reactivity or about asynchronous data that needs to be loaded.

async fn resolve(self) -> <ArcSignal<V> as InnerHtmlValue>::AsyncOutput

“Resolves” this into a type that is not waiting for any asynchronous data.

impl<V> IntoClass for ArcSignal<V>

where V: IntoClass + Clone + Send + Sync + 'static, <V as IntoClass>::State: 'static, ArcSignal<V>: Get<Value = V>,

type AsyncOutput = ArcSignal<V>

The type after all async data have resolved.

type State = RenderEffect<<V as IntoClass>::State>

The view state retained between building and rebuilding.

type Cloneable = ArcSignal<V>

An equivalent value that can be cloned.

type CloneableOwned = ArcSignal<V>

An equivalent value that can be cloned and is 'static.

fn html_len(&self) -> usize

The estimated length of the HTML.

fn to_html(self, class: &mut String)

Renders the class to HTML.

fn hydrate<const FROM_SERVER: bool>( self, el: &Element, ) -> <ArcSignal<V> as IntoClass>::State

Adds interactivity as necessary, given DOM nodes that were created from HTML that has either been rendered on the server, or cloned for a <template>.

fn build(self, el: &Element) -> <ArcSignal<V> as IntoClass>::State

Adds this class to the element during client-side rendering.

fn rebuild(self, state: &mut <ArcSignal<V> as IntoClass>::State)

Updates the value.

fn into_cloneable(self) -> <ArcSignal<V> as IntoClass>::Cloneable

Converts this to a cloneable type.

fn into_cloneable_owned(self) -> <ArcSignal<V> as IntoClass>::CloneableOwned

Converts this to a cloneable, owned type.

fn dry_resolve(&mut self)

“Runs” the attribute without other side effects. For primitive types, this is a no-op. For reactive types, this can be used to gather data about reactivity or about asynchronous data that needs to be loaded.

async fn resolve(self) -> <ArcSignal<V> as IntoClass>::AsyncOutput

“Resolves” this into a type that is not waiting for any asynchronous data.

fn reset(state: &mut <ArcSignal<V> as IntoClass>::State)

Reset the class list to the state before this class was added.

const TEMPLATE: &'static str = ""

The HTML that should be included in a <template>.

const MIN_LENGTH: usize = _

The minimum length of the HTML.

fn to_template(class: &mut String)

Renders the class to HTML for a <template>.

impl<V> IntoProperty for ArcSignal<V>

where V: IntoProperty + Clone + Send + Sync + 'static, <V as IntoProperty>::State: 'static, ArcSignal<V>: Get<Value = V>,

type State = RenderEffect<<V as IntoProperty>::State>

The view state retained between building and rebuilding.

type Cloneable = ArcSignal<V>

An equivalent value that can be cloned.

type CloneableOwned = ArcSignal<V>

An equivalent value that can be cloned and is 'static.

fn hydrate<const FROM_SERVER: bool>( self, el: &Element, key: &str, ) -> <ArcSignal<V> as IntoProperty>::State

Adds the property on an element created from HTML.

fn build(self, el: &Element, key: &str) -> <ArcSignal<V> as IntoProperty>::State

Adds the property during client-side rendering.

fn rebuild(self, state: &mut <ArcSignal<V> as IntoProperty>::State, key: &str)

Updates the property with a new value.

fn into_cloneable(self) -> <ArcSignal<V> as IntoProperty>::Cloneable

Converts this to a cloneable type.

fn into_cloneable_owned(self) -> <ArcSignal<V> as IntoProperty>::CloneableOwned

Converts this to a cloneable, owned type.

impl<V> IntoStyle for ArcSignal<V>

where V: IntoStyle + Clone + Send + Sync + 'static, <V as IntoStyle>::State: 'static, ArcSignal<V>: Get<Value = V>,

type AsyncOutput = ArcSignal<V>

The type after all async data have resolved.

type State = RenderEffect<<V as IntoStyle>::State>

The view state retained between building and rebuilding.

type Cloneable = ArcSignal<V>

An equivalent value that can be cloned.

type CloneableOwned = ArcSignal<V>

An equivalent value that can be cloned and is 'static.

fn to_html(self, style: &mut String)

Renders the style to HTML.

fn hydrate<const FROM_SERVER: bool>( self, el: &Element, ) -> <ArcSignal<V> as IntoStyle>::State

Adds interactivity as necessary, given DOM nodes that were created from HTML that has either been rendered on the server, or cloned for a <template>.

fn build(self, el: &Element) -> <ArcSignal<V> as IntoStyle>::State

Adds this style to the element during client-side rendering.

fn rebuild(self, state: &mut <ArcSignal<V> as IntoStyle>::State)

Updates the value.

fn into_cloneable(self) -> <ArcSignal<V> as IntoStyle>::Cloneable

Converts this to a cloneable type.

fn into_cloneable_owned(self) -> <ArcSignal<V> as IntoStyle>::CloneableOwned

Converts this to a cloneable, owned type.

fn dry_resolve(&mut self)

“Runs” the attribute without other side effects. For primitive types, this is a no-op. For reactive types, this can be used to gather data about reactivity or about asynchronous data that needs to be loaded.

async fn resolve(self) -> <ArcSignal<V> as IntoStyle>::AsyncOutput

“Resolves” this into a type that is not waiting for any asynchronous data.

fn reset(state: &mut <ArcSignal<V> as IntoStyle>::State)

Reset the styling to the state before this style was added.

impl<V> IntoStyleValue for ArcSignal<V>

where V: IntoStyleValue + Send + Sync + Clone + 'static, ArcSignal<V>: Get<Value = V>,

type AsyncOutput = ArcSignal<V>

The type after all async data have resolved.

type State = (Arc<str>, RenderEffect<<V as IntoStyleValue>::State>)

The view state retained between building and rebuilding.

type Cloneable = ArcSignal<V>

An equivalent value that can be cloned.

type CloneableOwned = ArcSignal<V>

An equivalent value that can be cloned and is 'static.

fn to_html(self, name: &str, style: &mut String)

Renders the style to HTML.

fn build( self, style: &CssStyleDeclaration, name: &str, ) -> <ArcSignal<V> as IntoStyleValue>::State

Adds this style to the element during client-side rendering.

fn rebuild( self, style: &CssStyleDeclaration, name: &str, state: &mut <ArcSignal<V> as IntoStyleValue>::State, )

Updates the value.

fn hydrate( self, style: &CssStyleDeclaration, name: &str, ) -> <ArcSignal<V> as IntoStyleValue>::State

Adds interactivity as necessary, given DOM nodes that were created from HTML that has either been rendered on the server, or cloned for a <template>.

fn into_cloneable(self) -> <ArcSignal<V> as IntoStyleValue>::Cloneable

Converts this to a cloneable type.

fn into_cloneable_owned( self, ) -> <ArcSignal<V> as IntoStyleValue>::CloneableOwned

Converts this to a cloneable, owned type.

fn dry_resolve(&mut self)

“Runs” the attribute without other side effects. For primitive types, this is a no-op. For reactive types, this can be used to gather data about reactivity or about asynchronous data that needs to be loaded.

async fn resolve(self) -> <ArcSignal<V> as IntoStyleValue>::AsyncOutput

“Resolves” this into a type that is not waiting for any asynchronous data.

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

where S: Storage<T>,

fn eq(&self, other: &ArcSignal<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 ArcSignal<T, S>

where S: Storage<T>,

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

Overriding the default auto implemented Read::try_read to combine read and track, to avoid 2 clones and just have 1 in the SignalTypes::DerivedSignal.

type Value = ReadGuard<T, SignalReadGuard<T, S>>

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

fn try_read_untracked( &self, ) -> Option<<ArcSignal<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.

impl<V> Render for ArcSignal<V>

where V: Render + Clone + Send + Sync + 'static, <V as Render>::State: 'static, ArcSignal<V>: Get<Value = V>,

type State = RenderEffectState<<V as Render>::State>

The “view state” for this type, which can be retained between updates.

fn build(self) -> <ArcSignal<V> as Render>::State

Creates the view for the first time, without hydrating from existing HTML.

fn rebuild(self, state: &mut <ArcSignal<V> as Render>::State)

Updates the view with new data.

impl<V> RenderHtml for ArcSignal<V>

where V: RenderHtml + Clone + Send + Sync + 'static, <V as Render>::State: 'static, ArcSignal<V>: Get<Value = V>,

const MIN_LENGTH: usize = 0

The minimum length of HTML created when this view is rendered.

type AsyncOutput = ArcSignal<V>

The type of the view after waiting for all asynchronous data to load.

type Owned = ArcSignal<V>

An equivalent value that is 'static.

fn dry_resolve(&mut self)

“Runs” the view without other side effects. For primitive types, this is a no-op. For reactive types, this can be used to gather data about reactivity or about asynchronous data that needs to be loaded.

async fn resolve(self) -> <ArcSignal<V> as RenderHtml>::AsyncOutput

Waits for any asynchronous sections of the view to load and returns the output.

fn html_len(&self) -> usize

An estimated length for this view, when rendered to HTML.

fn to_html_with_buf( self, buf: &mut String, position: &mut Position, escape: bool, mark_branches: bool, extra_attrs: Vec<AnyAttribute>, )

Renders a view to HTML, writing it into the given buffer.

fn to_html_async_with_buf<const OUT_OF_ORDER: bool>( self, buf: &mut StreamBuilder, position: &mut Position, escape: bool, mark_branches: bool, extra_attrs: Vec<AnyAttribute>, )

where ArcSignal<V>: Sized,

Renders a view into a buffer of (synchronous or asynchronous) HTML chunks.

fn hydrate<const FROM_SERVER: bool>( self, cursor: &Cursor, position: &PositionState, ) -> <ArcSignal<V> as Render>::State

Makes a set of DOM nodes rendered from HTML interactive.

fn into_owned(self) -> <ArcSignal<V> as RenderHtml>::Owned

Convert into the equivalent value that is 'static.

const EXISTS: bool = true

Whether this should actually exist in the DOM, if it is the child of an element.

fn to_html(self) -> String

where Self: Sized,

Renders a view to an HTML string.

fn to_html_branching(self) -> String

where Self: Sized,

Renders a view to HTML with branch markers. This can be used to support libraries that diff HTML pages against one another, by marking sections of the view that branch to different types with marker comments.

fn to_html_stream_in_order(self) -> StreamBuilder

where Self: Sized,

Renders a view to an in-order stream of HTML.

fn to_html_stream_in_order_branching(self) -> StreamBuilder

where Self: Sized,

Renders a view to an in-order stream of HTML with branch markers. This can be used to support libraries that diff HTML pages against one another, by marking sections of the view that branch to different types with marker comments.

fn to_html_stream_out_of_order(self) -> StreamBuilder

where Self: Sized,

Renders a view to an out-of-order stream of HTML.

fn to_html_stream_out_of_order_branching(self) -> StreamBuilder

where Self: Sized,

Renders a view to an out-of-order stream of HTML with branch markers. This can be used to support libraries that diff HTML pages against one another, by marking sections of the view that branch to different types with marker comments.

fn hydrate_async( self, cursor: &Cursor, position: &PositionState, ) -> impl Future<Output = Self::State>

Asynchronously makes a set of DOM nodes rendered from HTML interactive.

fn hydrate_from<const FROM_SERVER: bool>(self, el: &Element) -> Self::State

where Self: Sized,

Hydrates using RenderHtml::hydrate, beginning at the given element.

fn hydrate_from_position<const FROM_SERVER: bool>( self, el: &Element, position: Position, ) -> Self::State

where Self: Sized,

Hydrates using RenderHtml::hydrate, beginning at the given element and position.

impl<T, S> Track for ArcSignal<T, S>

where S: Storage<T>,

fn track(&self)

Subscribes to this signal in the current reactive scope without doing anything with its value.

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

where S: Storage<T>,