Struct Computed 

pub struct Computed<T: Clone> { /* private fields */ }

A reactive value that is read-only and computed by dependency graph.

Computed directly from Value

use vertigo::{Value, transaction};

let value = Value::new(5);

let comp = value.to_computed();

transaction(|context| {
    assert_eq!(comp.get(context), 5);
});

// Can't do that
// comp.set(10);

Computed from Value by provided function

use vertigo::{Computed, Value, transaction};

let value = Value::new(2);

let comp_2 = {
    let v = value.clone();
    Computed::from(move |context| v.get(context) * 2)
};

transaction(|context| {
    assert_eq!(comp_2.get(context), 4);
});

value.set(6);

transaction(|context| {
    assert_eq!(comp_2.get(context), 12);
});

Implementations

impl<T: Clone + 'static> Computed<T>

pub fn from<F: Fn(&Context) -> T + 'static>(get_value: F) -> Computed<T>

Creates new Computed<T> which state is determined by provided generator function.

pub fn get(&self, context: &Context) -> T

Get current value, it will be computed on-the-fly if the previous one ran out of date.

pub fn map<K: Clone + 'static, F: 'static + Fn(T) -> K>( &self, fun: F, ) -> Computed<K>

Reactively convert Computed<T> to Computed<K> with provided transformation function applied.

pub fn id(&self) -> GraphId

pub fn subscribe_all<R: 'static, F: Fn(T) -> R + 'static>( self, callback: F, ) -> DropResource

Do something every time the value inside Computed is triggered.

Note that the callback is fired every time the value in Computed is computed, even if the outcome value is not changed.

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

pub fn subscribe<R: 'static, F: Fn(T) -> R + 'static>( self, callback: F, ) -> DropResource

Do something every time the value inside Computed is changed.

Note that the callback is fired only if the value really changes. This means that even if computation takes place with different source value, but the resulting value is the same as old one, the callback is not fired.

pub fn render_value(&self, render: impl Fn(T) -> DomNode + 'static) -> DomNode

Render value inside this Computed. See Value::render_value() for examples.

pub fn render_value_option( &self, render: impl Fn(T) -> Option<DomNode> + 'static, ) -> DomNode

Render optional value inside this Computed. See Value::render_value_option() for examples.

impl<T: Clone + PartialEq + 'static, L: IntoIterator<Item = T> + Clone + 'static> Computed<L>

pub fn render_list<K: Eq + Hash>( &self, get_key: impl Fn(&T) -> K + 'static, render: impl Fn(&T) -> DomNode + 'static, ) -> DomNode

Render iterable value inside this Computed. See Value::render_list() for examples.

Trait Implementations

impl<T: Clone + 'static> Clone for Computed<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: ToString + Clone + PartialEq + 'static> EmbedDom for &Computed<T>

fn embed(self) -> DomNode

impl<T: ToString + Clone + PartialEq + 'static> EmbedDom for Computed<T>

fn embed(self) -> DomNode

impl From<&Computed<Option<String>>> for AttrValue

fn from(value: &Computed<Option<String>>) -> Self

Converts to this type from the input type.

impl<T: Clone + 'static> From<&T> for Computed<T>

fn from(value: &T) -> Self

Converts to this type from the input type.

impl From<&str> for Computed<String>

fn from(value: &str) -> Self

Converts to this type from the input type.

impl From<Computed<Css>> for CssAttrValue

fn from(value: Computed<Css>) -> Self

Converts to this type from the input type.

impl From<Computed<Option<String>>> for AttrValue

fn from(value: Computed<Option<String>>) -> Self

Converts to this type from the input type.

impl<R> From<Computed<Rc<dyn Fn() -> R>>> for Callback<R>

fn from(value: Computed<Rc<dyn Fn() -> R + 'static>>) -> Self

Converts to this type from the input type.

impl<T, R> From<Computed<Rc<dyn Fn(T) -> R>>> for Callback1<T, R>

fn from(value: Computed<Rc<dyn Fn(T) -> R + 'static>>) -> Self

Converts to this type from the input type.

impl From<Computed<String>> for AttrValue

fn from(value: Computed<String>) -> Self

Converts to this type from the input type.

impl<T: Clone + 'static> From<T> for Computed<T>

fn from(value: T) -> Self

Converts to this type from the input type.

impl<T: Clone + 'static> From<Value<T>> for Computed<T>

fn from(val: Value<T>) -> Self

Converts to this type from the input type.

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

fn eq(&self, other: &Self) -> 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: Clone + 'static> ToComputed<Resource<Rc<T>>> for Computed<Resource<T>>

fn to_computed(&self) -> Computed<Resource<Rc<T>>>

impl<T: Clone + 'static> ToComputed<T> for &Computed<T>

fn to_computed(&self) -> Computed<T>

impl<T: Clone + 'static> ToComputed<T> for Computed<T>

fn to_computed(&self) -> Computed<T>