Struct redux_rs::middlewares::thunk::ThunkMiddleware

source · [−]

pub struct ThunkMiddleware;

Expand description

Thunk middleware

Thunk middleware enables us to introduce side-effects in a redux application.

With this middleware you can dispatch actions and thunks to your store.

Fn example

use async_trait::async_trait;
use std::sync::Arc;
use std::time::Duration;
use redux_rs::{Store, StoreApi};
use redux_rs::middlewares::thunk::{ActionOrThunk, ThunkMiddleware, Thunk};
use tokio::time::sleep;

#[derive(Default, Debug, PartialEq)]
struct UserState {
    users: Vec<User>,
}

#[derive(Clone, Debug, PartialEq)]
struct User {
    id: u8,
    name: String,
}

enum UserAction {
    UsersLoaded { users: Vec<User> },
}

fn user_reducer(state: UserState, action: UserAction) -> UserState {
    match action {
        UserAction::UsersLoaded { users } => UserState { users },
    }
}

async fn load_users(store_api: Arc<impl StoreApi<UserState, UserAction>>) {
    // Emulate api call by delaying for 100 ms
    sleep(Duration::from_millis(100)).await;

    // Return the data to the store
    store_api
        .dispatch(UserAction::UsersLoaded {
            users: vec![
                User {
                    id: 0,
                    name: "John Doe".to_string(),
                },
                User {
                    id: 1,
                    name: "Jane Doe".to_string(),
                },
            ],
        })
        .await;
}
let store = Store::new(user_reducer).wrap(ThunkMiddleware).await;
store.dispatch(ActionOrThunk::Thunk(Box::new(load_users))).await;

let users = store.select(|state: &UserState| state.users.clone()).await;
assert_eq!(users, vec![]);

sleep(Duration::from_millis(200)).await;

let users = store.select(|state: &UserState| state.users.clone()).await;
assert_eq!(
    users,
    vec![
        User {
            id: 0,
            name: "John Doe".to_string(),
        },
        User {
            id: 1,
            name: "Jane Doe".to_string(),
        },
    ]
);

Trait example

use async_trait::async_trait;
use std::sync::Arc;
use std::time::Duration;
use redux_rs::{Store, StoreApi};
use redux_rs::middlewares::thunk::{ActionOrThunk, ThunkMiddleware, Thunk};
use tokio::time::sleep;

#[derive(Default, Debug, PartialEq)]
struct UserState {
    users: Vec<User>,
}

#[derive(Clone, Debug, PartialEq)]
struct User {
    id: u8,
    name: String,
}

enum UserAction {
    UsersLoaded { users: Vec<User> },
}

fn user_reducer(state: UserState, action: UserAction) -> UserState {
    match action {
        UserAction::UsersLoaded { users } => UserState { users },
    }
}

struct LoadUsersThunk;
#[async_trait]
impl<Api> Thunk<UserState, UserAction, Api> for LoadUsersThunk
    where
        Api: StoreApi<UserState, UserAction> + Send + Sync + 'static,
{
    async fn execute(&self, store_api: Arc<Api>) {
        // Emulate api call by delaying for 100 ms
        sleep(Duration::from_millis(100)).await;

        // Return the data to the store
        store_api
            .dispatch(UserAction::UsersLoaded {
                users: vec![
                    User {
                        id: 0,
                        name: "John Doe".to_string(),
                    },
                    User {
                        id: 1,
                        name: "Jane Doe".to_string(),
                    },
                ],
            })
            .await;
    }
}
let store = Store::new(user_reducer).wrap(ThunkMiddleware).await;
store.dispatch(ActionOrThunk::Thunk(Box::new(LoadUsersThunk))).await;

let users = store.select(|state: &UserState| state.users.clone()).await;
assert_eq!(users, vec![]);

sleep(Duration::from_millis(200)).await;

let users = store.select(|state: &UserState| state.users.clone()).await;
assert_eq!(
    users,
    vec![
        User {
            id: 0,
            name: "John Doe".to_string(),
        },
        User {
            id: 1,
            name: "Jane Doe".to_string(),
        },
    ]
);