Struct Value

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

Expand description

A reactive value. Basic building block of app state.

Can be read or written.

use vertigo::{Value, transaction};

let value = Value::new(5);

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

value.set(10);

transaction(|context| {
    assert_eq!(value.get(context), 10);
});

Implementations§

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

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pub fn new(value: T) -> Self

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pub fn with_connect<F>(value: T, create: F) -> Computed<T>
where F: Fn(&Value<T>) -> DropResource + 'static,

Create a value that is connected to a generator, where value parameter is a starting value, and create function takes care of updating it.

See Router implementation for example example.

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pub fn set_force(&self, value: T)

Allows to set a new value if T doesn’t implement PartialEq.

This will always trigger a graph change even if the value stays the same.

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

Get the value.

Use this in callbacks. You can get Context object using transaction function. During rendering you should directly embed the Value in dom! or use .render_value() method.

Returned T is cloned - it’s not reactive.

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

Reactively convert Value into Computed with provided transformation function applied.

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pub fn id(&self) -> GraphId

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pub fn deps(&self) -> &'static Dependencies

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

Reactively convert the `Value`` into Computed without any mapping.

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

Render value (reactively transforms T into DomNode)

See computed_tuple if you want to render multiple values in a handy way.

use vertigo::{dom, Value};

let my_value = Value::new(5);

let element = my_value.render_value(|bare_value| dom! { <div>{bare_value}</div> });

dom! {
    <div>
        {element}
    </div>
};

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

Render optional value (reactively transforms Option<T> into Option<DomNode>)

See computed_tuple if you want to render multiple values in a handy way.

use vertigo::{dom, Value};

let value1 = Value::new(Some(5));
let value2 = Value::new(None::<i32>);

let element1 = value1.render_value_option(|bare_value|
    bare_value.map(|value| dom! { <div>{value}</div> })
);
let element2 = value2.render_value_option(|bare_value|
    match bare_value {
        Some(value) => Some(dom! { <div>{value}</div> }),
        None => Some(dom! { <div>"default"</div> }),
    }
);

dom! {
    <div>
        {element1}
        {element2}
    </div>
};

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

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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 (reactively transforms Iterator<T> into Node with list of rendered elements )

use vertigo::{dom, Value};

let my_list = Value::new(vec![
    (1, "one"),
    (2, "two"),
    (3, "three"),
]);

let elements = my_list.render_list(
    |el| el.0,
    |el| dom! { <div>{el.1}</div> }
);

dom! {
    <div>
        {elements}
    </div>
};