Trait Selector 

pub trait Selector<S: AppState> {
    type Output;

    // Required method
    fn select(view: &View<'_, S>) -> Self::Output;
}

A selector that derives a value from the View.

Selectors extract and transform data from state so widgets can depend on derived values without coupling to the full state shape.

Example

struct ItemCount;
impl Selector<MyState> for ItemCount {
    type Output = usize;
    fn select(view: &View<MyState>) -> usize {
        view.state.items.len()
    }
}

// In a widget:
let count: usize = view.select::<ItemCount>();

Required Associated Types

type Output

The type produced by the selector.

Required Methods

fn select(view: &View<'_, S>) -> Self::Output

Extract the value from the given view.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors