yewdux 0.9.3

Ergonomic state management for Yew applications
Documentation 
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//! Unique state shared application-wide
use std::{future::Future, rc::Rc};

use async_trait::async_trait;

pub use yewdux_macros::Store;

/// Globally shared state.
pub trait Store: 'static {
    /// Create this store.
    fn new() -> Self;

    /// Indicate whether or not subscribers should be notified about this change. Usually this
    /// should be set to `self != old`.
    fn should_notify(&self, old: &Self) -> bool;
}

/// A type that can change state.
///
/// ```
/// use std::rc::Rc;
///
/// use yew::prelude::*;
/// use yewdux::prelude::*;
///
/// #[derive(Default, Clone, PartialEq, Eq, Store)]
/// struct Counter {
///     count: u32,
/// }
///
/// enum Msg {
///     AddOne,
/// }
///
/// impl Reducer<Counter> for Msg {
///     fn apply(self, mut counter: Rc<Counter>) -> Rc<Counter> {
///         let state = Rc::make_mut(&mut counter);
///         match self {
///             Msg::AddOne => state.count += 1,
///         };
///
///         counter
///     }
/// }
///
/// #[function_component]
/// fn App() -> Html {
///     let (counter, dispatch) = use_store::<Counter>();
///     let onclick = dispatch.apply_callback(|_| Msg::AddOne);
///
///     html! {
///         <>
///         <p>{ counter.count }</p>
///         <button {onclick}>{"+1"}</button>
///         </>
///     }
/// }
/// ```
pub trait Reducer<S> {
    /// Mutate state.
    fn apply(self, state: Rc<S>) -> Rc<S>;
}

impl<F, S> Reducer<S> for F
where
    F: FnOnce(Rc<S>) -> Rc<S>,
{
    fn apply(self, state: Rc<S>) -> Rc<S> {
        self(state)
    }
}

/// A type that can change state asynchronously.
///
/// # Example
///
/// ```
/// use std::rc::Rc;
///
/// use yewdux::prelude::*;
///
/// #[derive(Default, Clone, PartialEq, Eq, Store)]
/// struct State {
///     count: u32,
/// }
///
/// struct MyReducer;
///
/// #[async_reducer]
/// impl AsyncReducer<State> for MyReducer {
///     /// Mutate state.
///     async fn apply(self, state: Rc<State>) -> Rc<State> {
///         // do async things
///         state
///     }
/// }
/// ```
///
/// **IMPORTANT**: note the extra `?Send` for the async trait definition. This is required for
/// `AsyncReducer`.
#[async_trait(?Send)]
pub trait AsyncReducer<S> {
    /// Mutate state.
    async fn apply(self, state: Rc<S>) -> Rc<S>;
}

#[async_trait(?Send)]
impl<F, FU, S> AsyncReducer<S> for F
where
    S: 'static,
    F: FnOnce(Rc<S>) -> FU,
    FU: Future<Output = Rc<S>>,
{
    async fn apply(self, state: Rc<S>) -> Rc<S> {
        self(state).await
    }
}