Function avalanche::hooks::state

pub fn state<'a, T: 'static, F: FnOnce() -> T>(
    ctx: Context<'a>, 
    f: F
) -> (Tracked<&'a T>, StateSetter<T>)

A hook that allows a component to keep persistent state across renders.

state takes a type parameter T specifying the type of the state variable the hook manages, as well as a parameter F specifying the type of a function providing a default value for T. On first call, the given state will be initialized with f; it will not be called on subsequent calls of the same state call site. The return value contains a tracked reference to the current state, and the setter StateSetter. &T’s lifetime is only valid within the component’s render function, but StateSetter may be freely moved and cloned.

To update the state, use the set or update methods on the setter variable.

Example

use avalanche::{component, tracked, View, state};
use avalanche_web::components::{Div, H2, Button, Text};

#[component]
fn Counter() -> View {
    let (count, set_count) = state(self, || 0);
    Div!(
        children: [
            H2!(
                child: Text!("Counter!"),
            ),
            Button!(
                on_click: move |_| set_count.update(|count| *count += 1),
                child: Text!("+")
            ),
            Text!(tracked!(count))
        ]
    )
}

Adapted from the avalanche_web counter example.