Module kayrx_ui::fabric::state

The Redux implementation for Rust .

Redux provides a clean way of managing states in an application. It could be user data such as preferences or information about the state of the program.

Concepts

In Redux data is immutable. The only way to change it is to take it and create some new data by following a set of rules.

State

A state is the form of data Redux manages. Theoretically it can be anything, but for an easy explanation let's take the following example: We have a simple counter application. It does nothing more than counting. Our state would look the following:

#[derive(Default)]
struct State {
    counter: i8
}

Actions

To change the state we need to dispatch actions. In Rust, they would usually be represented by an enum. For the counter, we want to increment and decrement it.

enum Action {
    Increment,
    Decrement
}

Reducer

To actually change the state (read: create a new one), we need what is called a reducer. It is a simple function which takes in the current state plus the action to perform and returns a new state.

fn reducer(state: &State, action: &Action) -> State {
    match action {
        Action::Increment => State {
            counter: state.counter + 1
        },
        Action::Decrement => State {
            counter: state.counter - 1
        }
    }
}

Note how the reducer uses the old data to create a new state.

Store

To put it all together, we use a store which keeps track of a state and provides an easy to use API for dispatching actions. The store takes the reducer and an initial state.

// The store needs to be mutable as it will change its inner state when dispatching actions.
let mut store = kayrx_ui::fabric::state::Store::new(reducer, State::default());

// Let it do its highly complex math.
store.dispatch(Action::Increment);
store.dispatch(Action::Decrement);

// Print the current count.
println!("{}", store.state().counter);

Subscriptions

Sometimes one might want to listen to changes happening. This is where subscriptions come in. They are callbacks with the current state that get called whenever an action gets dispatched.

store.subscribe(|state: &State| {
     println!("Something changed! Current value: {}", state.counter);
});

Structs

Store

A container holding a state and providing the possibility to dispatch actions.

Type Definitions

Middleware
Reducer	Function signature for a reducer.
Subscription	Function signature for a subscription.